Battery cell and battery

Abstract

The utility model discloses a kind of battery and electric core, the electric core includes: electric core body, electric core body includes mutually laminated winding setting first pole piece, diaphragm and second pole piece, first pole piece and second pole piece polarity is opposite;Wherein, at least one of first pole piece and second pole piece is pasted with adhesive paper and is formed with crease at pasting glue, adhesive paper has base material layer and is arranged on base material layer adhesive layer, the one side of adhesive layer back to base material layer is equipped with first recess, first recess covers crease.The utility model electric core can avoid adhesive paper to pole piece excessive pulling when swelling and shrinking in charge-discharge cycle process, reduce the risk that pole piece appears broken strip, effectively improve the stability of electric core structure.

Description

Technical Field

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

[0002] Lithium batteries are batteries that contain lithium (including metallic lithium, lithium alloys, lithium ions, and lithium polymers) in their electrochemical system and are widely used in consumer products and other fields.

[0003] Among lithium batteries on the market, the mainstream cell types include stacked cells and wound cells. Stacked cells are formed by stacking positive and negative electrodes and separators in sequence, which has advantages such as regular structure and low internal resistance. Wound cells are formed by winding positive and negative electrodes and separators in sequence, which has certain advantages in terms of production efficiency and cost control, and therefore occupies a considerable share of the market.

[0004] In practical applications, wound battery cells often require adhesive application due to varying product performance and safety requirements. For example, finishing tape is typically applied to the corners of the cell to secure the wound ends of the electrodes, ensuring structural stability. Tab tape is applied to the welding points of the tabs, protecting the solder joints and preventing short circuits. However, during charge-discharge cycles, the battery cell undergoes repeated expansion and contraction due to internal electrochemical reactions. This leads to frequent bending of the electrodes and the adhesive tape. Because of the strong adhesion between the tape and the electrodes, this adhesion exerts a pulling force on the electrodes during bending. As the number of charge-discharge cycles increases, the electrodes are prone to breakage under this sustained pulling force, severely impacting the battery's lifespan and safety, thus limiting the application of wound battery cells in scenarios with high reliability requirements. Utility Model Content

[0005] The main purpose of this utility model is to propose a battery cell that aims to solve the technical problem that the current wound battery cell is prone to breakage due to the large adhesive force of the adhesive paper pulling the electrode sheet during the charge and discharge cycle.

[0006] To achieve the above objectives, this utility model proposes a battery cell, which includes:

[0007] The battery cell body includes a first electrode, a separator, and a second electrode that are stacked and wound together, wherein the first electrode and the second electrode have opposite polarities.

[0008] In this embodiment, at least one of the first electrode and the second electrode is covered with adhesive tape and a crease is formed at the adhesive application point. The adhesive tape has a substrate layer and an adhesive layer disposed on the substrate layer. The side of the adhesive layer facing away from the substrate layer is provided with a first groove, which covers the crease.

[0009] Optionally, the thickness of the adhesive layer is D1, and the depth of the first groove is D2, satisfying: 0.5D1≤D2≤0.8D1.

[0010] Optionally, along the winding direction of the battery cell body, the width of the adhesive tape is L1, and the width of the first groove is L2, satisfying: 0.3L1≤L2≤0.7L1.

[0011] Optionally, the substrate layer has a plurality of second grooves on the side facing away from the adhesive layer. The plurality of second grooves are arranged at intervals along the width direction of the adhesive paper, and each second groove can expand or contract with the deformation of the adhesive paper.

[0012] Optionally, the thickness of the substrate layer is D3, and the depth of the second groove is D4, satisfying: 0.05D3≤D4≤0.1D3.

[0013] Optionally, the width of the second groove is L3, satisfying: 0.05mm≤L3≤0.1mm.

[0014] Optionally, the distance between any two adjacent second grooves is L4, satisfying: 1mm≤L4≤5mm.

[0015] Optionally, the cell body has two corner areas arranged opposite to each other along its width direction, and the first electrode has a long film surface and a short film surface respectively provided on both sides along its thickness direction;

[0016] The adhesive tape includes a first finishing adhesive tape, which is adhered to the end of the short film surface and located at one of the two corner areas; and / or, the adhesive tape includes a second finishing adhesive tape, which is adhered to the winding end of the first electrode sheet and located at one of the two corner areas.

[0017] Optionally, the first electrode sheet is provided with a first welding position for welding tabs, and the adhesive tape includes first tab adhesive tape, which is adhered to the first welding position; and / or,

[0018] The second electrode plate is provided with a second welding position for welding tabs, and the adhesive paper includes a second tab adhesive paper, which is adhered to the second welding position.

[0019] The present invention also proposes a battery comprising a casing and a battery cell as described above, wherein the battery cell is disposed in the casing.

[0020] During the charge-discharge cycle, the battery cell of this invention repeatedly expands and contracts, causing creases to form at the adhesive application points of the electrodes. By creating a first groove on the adhesive layer of the adhesive paper and covering the creases, the contact area between the adhesive paper and the bent electrode is directly reduced, thereby reducing the adhesive force of the adhesive paper at the bent electrode. When the battery cell expands and contracts during the charge-discharge cycle, excessive stretching of the adhesive paper on the electrodes can be avoided, reducing the risk of electrode breakage and effectively improving the stability of the battery cell structure. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the battery cell structure in one embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the adhesive tape of the battery cell being bonded to the first electrode in one embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the adhesive paper of the battery cell in one embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the adhesive paper structure of the battery cell in another embodiment of the present invention;

[0025] Explanation of icon numbers:

[0026] 100 Battery cell body 110 First Pole Film 120 diaphragm 130 Second pole plate 200 Adhesive tape R creases 210 Substrate layer 220 Adhesive layer 221 First groove 211 Second groove 201 First finishing tape 202 Second finishing tape 203 First-stage adhesive tape 204 Second pole ear tape

[0027] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0029] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0030] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0031] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0032] This utility model embodiment proposes a battery cell, referring to... Figure 1 and Figure 2 The battery cell includes:

[0033] The battery cell body 100 includes a first electrode 110, a separator 120 and a second electrode 130 that are stacked and wound together, wherein the first electrode 110 and the second electrode 130 have opposite polarities.

[0034] In this embodiment, at least one of the first electrode 110 and the second electrode 130 is covered with adhesive tape 200 and a crease R is formed at the adhesive application point. The adhesive tape 200 has a substrate layer 210 and an adhesive layer 220 disposed on the substrate layer 210. The side of the adhesive layer 220 facing away from the substrate layer 210 is provided with a first groove 221, which covers the crease R.

[0035] like Figure 1As shown, the battery cell body 100 involved in this embodiment, as the core basic structure of the battery cell, is formed by stacking and winding a first electrode 110, a separator 120, and a second electrode 130 in a specific order. The first electrode 110 and the second electrode 130 have opposite polarities. In practical applications, depending on the battery design requirements, the first electrode 110 can be set as the cathode electrode and the second electrode 130 as the anode electrode; or the first electrode 110 can be the anode electrode and the second electrode 130 as the cathode electrode. During battery discharge, the anode electrode serves as the source of lithium ions, undergoing a lithium ion extraction reaction; during charging, it undergoes a lithium ion insertion reaction. The cathode electrode serves as a lithium ion storage site during charging and receives lithium ions extracted from the anode electrode during discharge. The separator 120 is located between the anode and cathode plates. It has good insulation properties and ion permeability, which can effectively isolate the positive and negative plates and prevent them from directly contacting each other and causing a short circuit. At the same time, it allows lithium ions to pass through smoothly during charging and discharging, ensuring the smooth progress of the electrochemical reaction inside the battery.

[0036] Corresponding to the first electrode 110 and the second electrode 130, at least one of them is covered with adhesive tape 200. It is permissible for only the first electrode 110 to have adhesive tape 200 applied, or only the second electrode 130 to have adhesive tape 200 applied, or both the first electrode 110 and the second electrode 130 to have adhesive tape 200 applied. The type and placement of the adhesive tape 200 can be varied. For example, the adhesive tape 200 can be a finishing adhesive tape located at a corner of the cell body 100 and corresponding to the tail end of the electrode; or it can be tab adhesive tape located at a straight section of the cell body 100 and corresponding to the tab soldering position. This is merely an example and not a limitation.

[0037] The adhesive tape 200 is composed of a substrate layer 210 and an adhesive layer 220, which are stacked in the thickness direction of the adhesive tape 200. The substrate layer 210 can be made of materials with good flexibility and mechanical strength, such as polyethylene terephthalate (PET) or polypropylene (PP), to adapt to the volume changes of the battery cell during charging and discharging. The adhesive layer 220 can be made of acrylic adhesives, silicone adhesives, etc., to ensure that the adhesive tape 200 has appropriate adhesion to the electrode sheet.

[0038] At the adhesive bonding area of ​​the electrode, due to the volume change of the cell during charge and discharge cycles, it will bend and form a crease R. For example... Figure 2As shown, taking the first electrode 110 as an example, corresponding to the crease R, the adhesive layer 220 has a first groove 221. This first groove 221 is located on the side of the adhesive layer 220 facing away from the substrate layer 210, and can precisely cover the crease R. The presence of the first groove 221 changes the contact pattern between the adhesive tape 200 and the electrode, significantly reducing the contact area between them at the crease R. The shape of the first groove 221 can be arc-shaped, U-shaped, V-shaped, or other suitable shapes, as long as it can achieve the function of covering the crease R and reducing the contact area between the adhesive tape 200 and the electrode. Furthermore, the first groove 221 can be manufactured by processing methods such as laser thinning. The adhesive tape 200 has a middle position in its width direction, and the first groove 221 is located at the corresponding middle position.

[0039] When the battery cell of this embodiment is in the charge-discharge cycle, lithium ions will intercalate and deintercalate between the positive and negative electrodes, resulting in expansion and contraction of the battery cell. During this process, the electrode with adhesive tape 200 will also bend as the battery cell volume changes, forming a crease R at the adhesive application point. During the expansion and contraction of the battery cell, the curvature at the crease R is the greatest compared to other locations.

[0040] Because the adhesive layer 220 of the adhesive tape 200 has a first groove 221 covering the crease R, the contact area between the adhesive tape 200 and the electrode bending position (especially the crease R) is directly reduced. According to the principle of adhesion, the reduction in contact area will reduce the adhesive force of the adhesive tape 200 on the electrode crease R. For example, the adhesive force of the adhesive tape 200 can be reduced by 5%, 8%, or 10%. Therefore, when the battery cell expands and contracts, the tensile force of the adhesive tape 200 on the electrode also decreases, thereby avoiding excessive stretching of the electrode by the adhesive tape 200 and reducing the risk of electrode breakage.

[0041] In some embodiments, refer to Figure 3The adhesive layer 220 has a thickness of D1, and the first groove 221 has a depth of D2, satisfying the condition: 0.5D1≤D2≤0.8D1. In this embodiment, the thickness of the adhesive layer 220 is D1, and the depth D2 of the first groove 221 can be set within the range of 0.5D1 to 0.8D1. For example, the depth D2 of the first groove 221 can be set to 0.5D1, 0.65D1, 0.8D1, etc., selected according to actual needs. Since the adhesive layer 220 of the adhesive tape 200 has a first groove 221 covering the crease R, the contact area between the adhesive tape 200 and the electrode bending position (especially the crease R position) is directly reduced. By limiting 0.5D1≤D2≤0.8D1, a reasonable proportional relationship is formed between the depth of the first groove 221 and the thickness of the adhesive layer 220. When D2 is too small, the first groove 221 has little effect on reducing the contact area and lowering the adhesive force; when D2 is too large, it may excessively weaken the adhesive performance of the adhesive tape 200, causing the adhesive tape 200 to fail to effectively fix the electrode. However, when D2 is within the ratio range of 0.5D1 to 0.8D1, it can ensure a stable basic adhesive force between the adhesive tape 200 and the electrode while significantly reducing the adhesive force at bending positions (especially at the crease R). Based on the principle of adhesive force, the reduction in contact area and the reasonable groove depth allow for precise control of the adhesive force between the adhesive tape 200 and the electrode at bending positions (especially at the crease R). Therefore, when the battery cell expands and contracts, the tensile force of the adhesive tape 200 on the electrode is limited to a suitable range, effectively preventing excessive stretching of the adhesive tape 200 on the electrode and significantly reducing the risk of electrode breakage. In other words, by precisely defining the relationship between the thickness of the adhesive layer 220 and the depth of the first groove 221, this embodiment can more accurately control the contact area and adhesive force at the bending position (especially the crease R position) of the adhesive paper 200 and the electrode sheet while ensuring the necessary adhesive strength between the adhesive paper 200 and the electrode sheet.

[0042] In some embodiments, refer to Figure 3Along the winding direction of the battery cell body 100, the width of the adhesive tape 200 is L1, and the width of the first groove 221 is L2, satisfying: 0.3L1≤L2≤0.7L1. In this embodiment, along the winding direction of the battery cell body 100, the width of the adhesive tape 200 is L1, and the width L2 of the first groove 221 can be set within the range of 0.3L1 to 0.7L1. For example, the width L2 of the first groove 221 can be set to 0.3L1, 0.5L1, 0.7L1, etc., selected according to actual needs. Since the adhesive layer 220 of the adhesive tape 200 is provided with the first groove 221 covering the crease R, the contact area between the adhesive tape 200 and the electrode bending position (especially the crease R position) is directly reduced. By limiting the 0.3L1≤L2≤0.7L1 embodiment, the width of the first groove 221 and the width of the adhesive tape 200 form a reasonable proportional relationship. When L2 is too small, the coverage area of ​​the first groove 221 is limited, making it difficult to sufficiently reduce the adhesive force at the bending position (especially at the crease R position); when L2 is too large, it will excessively weaken the contact area between the adhesive tape 200 and the electrode, affecting the overall fixing effect of the adhesive tape 200 on the electrode. Within this ratio range, the first groove 221 can effectively cover the electrode crease R area in the cell winding direction, precisely controlling the contact area, thereby limiting the tensile force of the adhesive tape 200 on the electrode to a suitable range when the cell expands and contracts, further reducing the risk of electrode breakage. In other words, by reasonably limiting the relationship between the width of the adhesive tape 200 and the width of the first groove 221, this embodiment enables the first groove 221 to reduce the adhesive force at the bending position of the electrode sheet (especially the crease R position) while maintaining the overall fixing effect of the adhesive tape 200 on the electrode sheet. This avoids the situation where the fixing ability of the adhesive tape 200 decreases due to the groove being too wide, or the groove being too narrow to effectively reduce the adhesive force. This achieves a balance between reducing the risk of electrode sheet breakage and ensuring the fixing reliability of the adhesive tape 200, thereby optimizing the overall performance of the battery cell.

[0043] In some embodiments, refer to Figure 4 The substrate layer 210 has a plurality of second grooves 211 on the side facing away from the adhesive layer 220. The plurality of second grooves 211 are arranged at intervals along the width direction of the adhesive paper 200, and each second groove 211 can expand or contract with the deformation of the adhesive paper 200.

[0044] In this embodiment, a plurality of second grooves 211 are provided on the substrate layer 210, and the plurality of second grooves 211 are located on the side of the substrate layer 210 facing away from the adhesive layer 220. The plurality of second grooves 211 are arranged alternately along the width direction of the adhesive tape 200. The shape of the second grooves 211 can be arc-shaped, U-shaped, V-shaped, or other suitable shapes, and their dimensions are reasonably designed according to the overall specifications of the adhesive tape 200 and actual application requirements. Furthermore, the number of second grooves 211 can be four, six, or eight, and this embodiment does not limit this. Under normal battery cell conditions, the second grooves 211 are in their initial state; when the battery cell undergoes volume changes during charge-discharge cycles, causing the electrode and adhesive tape 200 to bend and deform, the second grooves 211 can expand or contract accordingly based on the degree of deformation, providing sufficient buffer space for the bending deformation of the adhesive tape 200, significantly reducing the resistance of the adhesive tape 200 during electrode deformation, avoiding excessive tensile force due to excessive resistance to electrode deformation by the adhesive tape 200, and further reducing the risk of electrode breakage. The second groove 211 works in conjunction with the first groove 221 to optimize the interaction between the adhesive tape 200 and the electrode from different angles. The first groove 221 reduces the contact area and lowers the adhesive force, while the second groove 211 reduces the deformation resistance. The two work together to reduce the adverse forces on the electrode during charge and discharge cycles from multiple directions, thereby improving the performance of the battery cell.

[0045] In some embodiments, refer to Figure 4The thickness of the substrate layer 210 is D3, and the depth of the second groove 211 is D4, satisfying the condition: 0.05D3≤D4≤0.1D3. In this embodiment, the thickness of the substrate layer 210 is D3, and the depth D4 of the second groove 211 can be set within the range of 0.05D3 to 0.1D3. For example, the depth D4 of the second groove 211 can be set to 0.05D3, 0.075D3, 0.1D3, etc., selected according to actual needs. This proportional relationship is set based on a balance between ensuring mechanical strength and flexibility of the adhesive tape 200 substrate layer 210 and realizing the function of the second groove 211. When D4 is less than 0.05D3, the second groove 211 is relatively shallow, which may not provide sufficient buffer space for the deformation of the adhesive tape 200, making it difficult to effectively reduce the resistance of the adhesive tape 200 during electrode deformation. When D4 is greater than 0.1D3, the second groove 211 is relatively deep, which may excessively weaken the strength of the substrate layer 210, causing the adhesive tape 200 to be easily damaged or lose stability when fixing the electrode. This embodiment precisely achieves a balance between the function and strength of the substrate layer 210 by limiting the relationship between the thickness D3 of the substrate layer 210 and the depth D4 of the second groove 211 to 0.05D3≤D4≤0.1D3. This ensures that the second groove 211 can provide sufficient and effective buffer space for the deformation of the adhesive tape 200, reducing the deformation resistance of the electrode, while maintaining the mechanical strength of the substrate layer 210, preventing the adhesive tape 200 from being damaged or its fixing performance from being too deep, and improving the reliability of the cell structure.

[0046] In some embodiments, refer to Figure 4The width of the second groove 211 is L3, satisfying the condition: 0.05mm ≤ L3 ≤ 0.1mm. In this embodiment, the width L3 of the second groove 211 can be set within the range of 0.05mm to 0.1mm. For example, the width L3 of the second groove 211 can be set to 0.05mm, 0.075mm, or 0.1mm, etc., selected according to actual needs. This width range setting fully considers the mitigation effect of the second groove 211 on the electrode deformation resistance in the width direction of the adhesive paper 200, as well as its impact on the overall structural strength of the adhesive paper 200. When L3 is less than 0.05mm, the second groove 211 is relatively too narrow, failing to effectively disperse the stress on the adhesive tape 200 during electrode deformation, making it difficult to significantly reduce the resistance of the adhesive tape 200 during electrode deformation. When L3 is greater than 0.1mm, the second groove 211 is relatively too wide, excessively weakening the strength of the substrate layer 210, affecting the fixing effect of the adhesive tape 200 on the electrode, and may even lead to problems such as tearing of the adhesive tape 200 during use. In this embodiment, by limiting the width L3 of the second groove 211 to 0.05mm≤L3≤0.1mm, the second groove 211 can efficiently disperse the stress generated during electrode deformation in the width direction of the adhesive tape 200 without excessively weakening the structural strength of the adhesive tape 200. The adhesive tape 200 can continuously and stably fix the electrode, achieving a balance between reducing the electrode deformation resistance and ensuring the fixing ability of the adhesive tape 200, thus optimizing the overall performance of the battery cell.

[0047] In some embodiments, refer to Figure 4The distance between any two adjacent second grooves 211 is L4, satisfying: 1mm ≤ L4 ≤ 5mm. In this embodiment, the distance L4 between two second grooves 211 in the width direction of the adhesive tape 200 can be set within the range of 1mm to 5mm. For example, the distance L4 between two second grooves 211 can be set to 1mm, 3mm, or 5mm, etc., and can be selected according to actual needs. The setting of this distance range fully considers the comprehensive influence of the second grooves 211 on the stress dispersion effect of the adhesive tape 200, the overall structural strength of the adhesive tape 200, and its compatibility with the electrode sheet. When L4 is less than 1 mm, the spacing between two adjacent second grooves 211 is too small, which can easily weaken the structural strength of the substrate layer 210 of the adhesive paper 200 and reduce the mechanical properties of the adhesive paper 200. At the same time, it may also cause the two adjacent second grooves 211 to affect each other when the adhesive paper 200 is deformed, and they cannot effectively play their respective buffering roles. When L4 is greater than 5 mm, the spacing between two adjacent second grooves 211 is too large, which makes it difficult to evenly distribute the stress generated by the deformation of the electrode in the width direction of the adhesive paper 200. It cannot fully reduce the resistance of the adhesive paper 200 during the deformation of the electrode, and weakens the role of the second grooves 211 in reducing the risk of electrode breakage. This embodiment limits the spacing L4 between any two adjacent second grooves 211 to 1mm≤L4≤5mm, so that the second grooves 211 form a reasonable layout in the width direction of the adhesive paper 200. This can efficiently and uniformly disperse the stress generated by the deformation of the electrode sheet, and avoid excessive weakening of the structural strength of the substrate layer 210 of the adhesive paper 200 due to the excessively close spacing of the second grooves 211. This ensures that the adhesive paper 200 maintains good mechanical properties during normal use and during the charging and discharging cycle of the battery cell.

[0048] In some embodiments, refer to Figure 1 The cell body 100 has two corner areas arranged opposite each other along its width direction, and the first electrode 110 has a long film surface and a short film surface respectively arranged on its two sides along its thickness direction.

[0049] The adhesive tape includes a first end adhesive tape 201, which is adhered to the end of the short film surface and located at one of the two corner areas; and / or, the adhesive tape includes a second end adhesive tape 202, which is adhered to the winding end of the first electrode 110 and located at one of the two corner areas.

[0050] In this embodiment, the first adhesive tape may include a first finishing adhesive tape 201, or a second finishing adhesive tape 202, or both the first finishing adhesive tape 201 and the second finishing adhesive tape 202.

[0051] The first finishing adhesive tape 201 is bonded to the end of the short film surface of the first electrode 110, which is tightly bonded thereto, and is located in a corner area in the width direction of the cell body 100. At this position, the first finishing adhesive tape 201 can effectively fix the end of the short film surface, and the relatively stable structure of the corner area enhances the fixing effect.

[0052] The second adhesive tape is bonded to the winding end of the first electrode 110 and is located in the corner area. It can also use the structural characteristics of the corner to firmly fix the winding end, prevent the winding end from loosening, and reduce the resistance of the adhesive tape to the normal deformation of the electrode.

[0053] The specific structures of the first finishing tape 201 and the second finishing tape 202 involved in this embodiment can be found in the description of the tape in the foregoing embodiments, and will not be described in detail here.

[0054] In some embodiments, refer to Figure 1 The first electrode 110 has a first welding position for welding tabs, and the adhesive tape includes a first tab adhesive tape 203, which is adhered to the first welding position; and / or,

[0055] The second electrode 130 is provided with a second welding position for welding electrode tabs, and the adhesive tape includes a second electrode tab adhesive tape 204, which is bonded to the second welding position.

[0056] In this embodiment, the first adhesive tape may include a first tab adhesive tape 203, a second tab adhesive tape 204, or both the first tab adhesive tape 203 and the second tab adhesive tape 204.

[0057] The welding point is a critical connection between the electrode and the tab. During cell charging and discharging, its volume changes, making it susceptible to external impacts and electrolyte corrosion. The tab adhesive tape, with its excellent insulation, prevents short circuits caused by contact between the welding point and other components. Its flexibility allows it to deform along with the electrode, preventing it from hindering normal electrode deformation due to its own hardness or damaging the welding point due to pulling, thus providing stable protection for the welding point and ensuring the reliability of the cell's electrical connection. Specifically, the first tab adhesive tape 203 is tightly adhered to the first welding point of the first electrode 110, completely covering the welding point and surrounding area, forming a protective barrier. Similarly, the second tab adhesive tape 204 is tightly bonded to the second welding point of the second electrode 130, tightly wrapping the welding area. These tab adhesive tapes adhere tightly to the electrode surface, providing reliable protection for the welding point without affecting normal electrode winding and cell assembly.

[0058] The specific structures of the first tab adhesive paper 203 and the second tab adhesive paper 204 involved in this embodiment can be found in the description of the adhesive paper in the foregoing embodiments, and will not be described in detail here.

[0059] This utility model embodiment also proposes a battery, which includes a casing and a battery cell as described in the foregoing embodiments, with the battery cell disposed within the casing. The specific structure of the battery cell is as described in the foregoing embodiments. Since this battery adopts all the technical solutions of all the foregoing embodiments, it possesses at least all the technical effects brought about by the technical solutions of the foregoing embodiments, and will not be elaborated upon here. The battery can be a lithium battery.

[0060] Specifically, based on the battery cell proposed in this solution, a room temperature cycle test can be performed to verify the battery cell's performance. During the test, the ambient temperature is set within the room temperature range (e.g., 25±2℃) and stabilized. The battery cell is then connected to a charging and discharging device, and the cycle is repeated according to a predetermined charging and discharging pattern, such as performing the following steps during the cycle:

[0061] Step 1: Let it stand for the first preset time (e.g., 5 minutes);

[0062] Step 2, charging, usually adopts the "constant current-constant voltage (CC-CV)" mode, such as 1C constant current charging to the cutoff voltage, and then constant voltage charging until the current ≤ 1C cutoff;

[0063] Step 3: Let it stand for the second preset time (e.g., 5 minutes);

[0064] Step 4, discharge, using a constant current (e.g., 1C, set according to the application scenario) to discharge to the lower limit voltage;

[0065] When a cell cracks, the number of cycles is recorded.

[0066] For detailed test information, please refer to the test table below (the unit of dimensions is mm):

[0067]

[0068] In this test table, the battery cell in the basic example uses adhesive tape 200 with adhesive layer 220 without first groove 221 and substrate layer 210 without second groove 221. The battery cell in Examples 1-3 uses adhesive tape 200 with adhesive layer 220 having first groove 221. The battery cell in Examples 4-7 uses adhesive tape 200 with adhesive layer 220 having first groove 221 and substrate layer 210 having second groove 211.

[0069] Comparing the basic example with Examples 1-3, it can be seen that the adhesive paper 200 with the adhesive layer 220 having the first groove 221 has a larger number of sharding cycles and better cell performance compared to the adhesive paper 200 without the first groove 221 in the adhesive layer 220. Furthermore, comparing Examples 1 and 2, it can be seen that the wider the width L2 of the first groove 221, the larger the number of sharding cycles and the better the cell performance. Comparing Examples 1 and 3, it can be seen that the deeper the depth D2 of the first groove 221, the larger the number of sharding cycles and the better the cell performance.

[0070] Based on the use of adhesive tape 200 with a first groove 221 in the adhesive layer 220 of the battery cell, a comparison of Examples 3 and 4-6 shows that the adhesive tape 200 with a second groove 211 in the substrate layer 210 of the battery cell has a larger number of sharding cycles and better electrical performance compared to the adhesive tape 200 without a second groove 211 in the substrate layer 210. Furthermore, a comparison of Examples 4 and 5 shows that the wider the width L3 of the second groove 211, the larger the number of sharding cycles and the better the battery cell performance. A comparison of Examples 4 and 6 shows that the shallower the depth D4 of the second groove 211, the larger the number of sharding cycles and the better the battery cell performance. A comparison of Examples 4 and 7 shows that the narrower the distance L4 between two adjacent second grooves 211, the larger the number of sharding cycles and the better the battery cell performance.

[0071] Furthermore, referring to the tape falling off ratio in each embodiment, it can be seen that the tape adheres firmly and is not easy to fall off during the battery cell charge-discharge cycle, demonstrating high stability.

[0072] Therefore, as the battery cell repeatedly expands and contracts during charge and discharge cycles, it bends at the adhesive application point of the electrode, forming creases. This poses a high risk of electrode breakage due to the strong adhesive force of the adhesive tape pulling the electrode. To address this, the battery cell can utilize adhesive tape 200 with a first groove 221 in the adhesive layer 220 or adhesive tape 200 with a first groove 221 in the adhesive layer 220 and a second groove 211 in the substrate layer 210. By optimizing the design of the width, depth, and other parameters of the first groove 221 and the second groove 211, the adhesive force of the adhesive tape 200 at the bending point of the electrode can be reduced. This avoids excessive pulling of the electrode by the adhesive tape 200, reduces the risk of electrode breakage, and improves the performance of the battery cell.

[0073] The above description is only a part or preferred embodiment of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the content of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.

Claims

1. A battery cell, characterized in that, include: The battery cell body (100) includes a first electrode (110), a separator (120), and a second electrode (130) that are stacked and wound together, wherein the first electrode (110) and the second electrode (130) have opposite polarities. In this embodiment, at least one of the first electrode (110) and the second electrode (130) is covered with adhesive tape (200) and a crease (R) is formed at the adhesive application point. The adhesive tape (200) has a substrate layer (210) and an adhesive layer (220) disposed on the substrate layer (210). The adhesive layer (220) has a first groove (221) on the side facing away from the substrate layer (210), and the first groove (221) covers the crease (R).

2. The battery cell according to claim 1, characterized in that, The thickness of the adhesive layer (220) is D1, and the depth of the first groove (221) is D2, satisfying: 0.5D1≤D2≤0.8D1.

3. The battery cell according to claim 1, characterized in that, Along the winding direction of the battery cell body (100), the width of the adhesive tape (200) is L1, and the width of the first groove (221) is L2, satisfying: 0.3L1≤L2≤0.7L1.

4. The battery cell according to claim 1, characterized in that, The substrate layer (210) has a plurality of second grooves (211) on the side facing away from the adhesive layer (220). The plurality of second grooves (211) are arranged at intervals along the width direction of the adhesive paper (200), and each second groove (211) can expand or contract with the deformation of the adhesive paper (200).

5. The battery cell according to claim 4, characterized in that, The thickness of the substrate layer (210) is D3, and the depth of the second groove (211) is D4, satisfying: 0.05D3≤D4≤0.1D3.

6. The battery cell according to claim 4, characterized in that, The width of the second groove (211) is L3, which satisfies: 0.05mm≤L3≤0.1mm.

7. The battery cell according to claim 4, characterized in that, The distance between any two adjacent second grooves (211) is L4, which satisfies: 1mm≤L4≤5mm.

8. The battery cell according to any one of claims 1 to 7, characterized in that, The cell body (100) has two corner areas arranged opposite to each other along its width direction, and the first electrode (110) has a long film surface and a short film surface respectively arranged on both sides along its thickness direction; The adhesive tape (200) includes a first end adhesive tape (201) which is adhered to the end of the short film surface and located at one of the two corner areas; and / or, the adhesive tape (200) includes a second end adhesive tape (202) which is adhered to the winding end of the first electrode (110) and located at one of the two corner areas.

9. The battery cell according to any one of claims 1 to 7, characterized in that, The first electrode plate (110) is provided with a first welding position for welding electrode tabs, and the adhesive tape (200) includes a first electrode tab adhesive tape (203), which is adhered to the first welding position; and / or, The second electrode (130) is provided with a second welding position for welding the electrode tab, and the adhesive tape (200) includes a second electrode tab adhesive tape (204), which is adhered to the second welding position.

10. A battery, characterized in that, It includes a housing and a battery cell as described in any one of claims 1 to 9, wherein the battery cell is disposed in the housing.

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