Battery cell, battery and electronic equipment

Abstract

The utility model relates to the technical field of batteries, in particular to a battery cell, a battery and electronic equipment. The battery cell comprises a positive pole piece, a negative pole piece and a diaphragm, the positive pole piece comprises a first straight section and a first corner section, the first corner section is connected to one end of the first straight section, the surfaces of the first straight section and the first corner section are coated with positive active material layers, and the positive active material layer of the first corner section is provided with a concave hole; the positive pole piece comprises a first straight section and a first corner section, the negative pole piece comprises a second straight section and a second corner section, the second corner section is connected to one end of the second straight section, the surfaces of the second straight section and the second corner section are coated with negative active material layers, the diaphragm is arranged between the positive pole piece and the negative pole piece, and a first coating layer is arranged on one side, close to the positive pole piece, of the diaphragm. And the concave hole is filled with the first coating layer. The battery comprises the battery cell. The electronic equipment comprises the battery. The battery cell is good in electrolyte infiltration effect, and the use safety of the battery cell, the battery and the electronic equipment can be ensured.

Description

Technical Field

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

[0002] In current technologies, with the continuous improvement of lithium battery manufacturing processes, the industry has placed higher demands on the performance and safety of lithium batteries. During lithium battery production, the corners of the battery cells experience significant localized stress, which can easily lead to poor electrolyte wetting at these corners. This restricts ion transport within the battery, making it prone to lithium plating at the corners. As the number of charge-discharge cycles increases, the amount of lithium plating within the battery also increases, potentially causing localized deformation at the corners and even lithium dendrites piercing the separator, exacerbating the risk of thermal runaway and affecting the safety of the lithium battery in use. Utility Model Content

[0003] The main purpose of this utility model is to propose a battery cell, battery and electronic device, which aims to solve the technical problem that lithium plating in the battery cell is easily caused by excessive local stress at the corner.

[0004] To achieve the above objectives, this utility model proposes a battery cell, comprising:

[0005] A positive electrode sheet, comprising a first straight section and a first corner section, the first corner section being connected to one end of the first straight section, the surfaces of the first straight section and the first corner section being coated with a positive active material layer, and the positive active material layer of the first corner section being provided with concave holes.

[0006] The negative electrode sheet includes a second straight section and a second corner section. The second corner section is connected to one end of the second straight section. The second straight section and the first straight section are arranged opposite to each other. The second corner section and the first corner section are arranged opposite to each other. The surfaces of the second straight section and the second corner section are coated with a negative electrode active material layer.

[0007] A separator is disposed between the positive electrode and the negative electrode. A first coating layer is disposed on the side of the separator closest to the positive electrode, and the first coating layer fills the recess.

[0008] In some embodiments, the negative electrode active material layer of the second corner segment is provided with a first groove, and the diaphragm is provided with a second coating layer on the side near the negative electrode sheet, the second coating layer filling the first groove.

[0009] In some embodiments, the negative electrode active material layer of the second corner segment is provided with a second groove, the second groove is connected to the first groove, and along the direction from the diaphragm to the negative electrode sheet, the projection of the second groove on the negative electrode sheet covers the projection of the first groove on the negative electrode sheet;

[0010] The second coating layer fills the second groove and the first groove.

[0011] In some embodiments, the length L1 of the first straight segment and the length L2 of the first corner segment satisfy the following condition: L1 > 1.5L2;

[0012] The length L3 of the second straight segment and the length L4 of the second corner segment satisfy the condition: L3 > 1.5L4.

[0013] In some embodiments, the length L5 of the first groove satisfies: 0.8L4≤L5≤1.2L4, and the groove depth D1 of the first groove satisfies: 5µm≤D1≤20µm;

[0014] The length L6 of the second groove satisfies: L4≤L6≤1.4L4, and the groove depth D2 of the second groove satisfies: 20µm≤D2≤50µm.

[0015] In some embodiments, the diameter φ of the concave hole satisfies: 100µm≤φ≤500µm; the depth D3 of the concave hole satisfies: 5µm≤D3≤80µm.

[0016] In some embodiments, the coating thickness D4 of the first coating layer at the first straight section satisfies: 0.5µm≤D4≤6µm, and the coating thickness D5 of the first coating layer at the first corner section satisfies: 10µm≤D5≤50µm.

[0017] The coating thickness D6 of the second coating layer at the second straight section satisfies: 0.5µm≤D6≤6µm, and the coating thickness D7 of the second coating layer at the second corner section satisfies: 10µm≤D7≤50µm.

[0018] In some embodiments, the total thickness X1 of the diaphragm at the first corner segment and the second corner segment satisfies: 0.8(X2+X3)≤X1≤(X2+X3);

[0019] Wherein, X2 is the maximum depth of the concave hole, and X3 is the maximum value of the sum of the groove depths of the first groove and the second groove.

[0020] Correspondingly, this utility model also proposes a battery, comprising:

[0021] The battery cell described in any of the above embodiments;

[0022] The battery cell is encapsulated within the housing.

[0023] Correspondingly, this utility model also proposes an electronic device, including the battery described in the above embodiments.

[0024] Compared with the prior art, the beneficial effects of this utility model are:

[0025] In the technical solution of this utility model, a concave hole is formed in the positive active material layer of the first corner section of the positive electrode sheet, and the first coating layer coated on the separator is filled into the concave hole. Since the first coating layer has good electrolyte absorption capacity, it can improve the wetting effect of the electrolyte on the positive electrode sheet. The concave hole is equivalent to constructing a fast lithium-ion transport channel, which allows lithium ions in the positive active material layer to be quickly transported to the electrolyte, and then transported to the negative active material layer through the electrolyte, realizing the charging and discharging of the battery cell. This prevents lithium plating caused by the concentration of lithium ion transport at the corner section of the battery cell (if lithium plating occurs at the corner of the battery cell, lithium dendrites will be generated, which pose a risk of lithium dendrites piercing the separator and causing direct contact between the positive and negative electrode sheets, resulting in an internal short circuit). This ensures that the battery cell will not experience an internal short circuit, eliminates the risk of thermal runaway of the battery cell, and improves the safety performance of the battery cell.

[0026] In addition, the first coating layer on the diaphragm is thickened corresponding to the recessed area, so that the first coating layer can fully fill the recessed area and compensate for the local stress unevenness caused by drilling holes in the positive electrode sheet.

[0027] The electrolyte in the aforementioned battery cells exhibits excellent wetting properties, which facilitates lithium-ion transport within the cell. Batteries using these cells can prevent lithium plating within the battery, thereby reducing the risk of thermal runaway and ensuring battery safety.

[0028] Electronic devices that use the aforementioned batteries can guarantee safe use. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a battery cell in a wound state according to an embodiment of the present invention;

[0031] Figure 2 A schematic diagram showing the unfolded state of the battery cell at the first corner segment and the second corner segment according to an embodiment of the present invention;

[0032] Figure 3 A schematic diagram showing the unfolded positive electrode plate in a battery cell according to an embodiment of this utility model;

[0033] Figure 4 A schematic diagram showing the unfolded negative electrode sheet in a battery cell according to an embodiment of this utility model;

[0034] Figure 5 This is a schematic diagram showing the unfolded structure of the separator in a battery cell according to an embodiment of the present invention.

[0035] Explanation of icon numbers:

[0036] 10. Battery cells;

[0037] 100. Positive electrode plate;

[0038] 110. First straight section; 120. First corner section; 130. Positive electrode active material layer;

[0039] 121. Concave hole;

[0040] 200. Negative electrode plate;

[0041] 210. Second straight section; 220. Second corner section; 230. Negative electrode active material layer;

[0042] 221. First groove; 222. Second groove;

[0043] 300. Diaphragm;

[0044] 310. First coating layer; 320. Second coating layer.

[0045] 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

[0046] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0047] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0048] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or," "and / or," or "and / or" throughout the text implies three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0049] In current technologies, with the continuous improvement of lithium battery manufacturing processes, the industry has placed higher demands on the performance and safety of lithium batteries. During lithium battery production, the corners of the battery cells experience significant localized stress, which can easily lead to poor electrolyte wetting at these corners. This restricts ion transport within the battery, making it prone to lithium plating at the corners. As the number of charge-discharge cycles increases, the amount of lithium plating within the battery also increases, potentially causing localized deformation at the corners and even lithium dendrites piercing the separator, exacerbating the risk of thermal runaway and affecting the safety of the lithium battery in use.

[0050] Based on this, in order to solve the technical problem that excessive local stress at the corner of cell 10 easily leads to lithium plating at the corner, referring to... Figures 1 to 5 One embodiment of this utility model provides a battery cell 10, which includes a positive electrode 100, a negative electrode 200, and a separator 300. For example, the battery cell 10 can be a wound battery cell 10.

[0051] The positive electrode 100 includes a first straight section 110 and a first corner section 120, with the first corner section 120 connected to one end of the first straight section 110. Both the first straight section 110 and the first corner section 120 are coated with a positive electrode active material layer 130, and the positive electrode active material layer 130 of the first corner section 120 has multiple recesses 121. For example, laser drilling can be used to create the multiple recesses 121 on the positive electrode active material layer 130 of the first corner section 120. The shape of the recesses 121 can be circular, regular polygonal, or other regularly shaped patterns. Preferably, the positive electrode 100 can be made of aluminum foil. The positive electrode active material layer 130 can be made of lithium compounds such as lithium cobalt oxide, lithium titanate, or lithium nickel cobalt manganese oxide.

[0052] The negative electrode 200 includes a second straight section 210 and a second corner section 220. The second corner section 220 is connected to one end of the second straight section 210. The second straight section 210 and the first straight section 110 are arranged opposite to each other, and the second corner section 220 and the first corner section 120 are arranged opposite to each other. Both the second straight section 210 and the corner section 220 are coated with a negative electrode active material layer 230. Furthermore, the negative electrode active material layer 230 and the positive electrode active material layer 130 are arranged opposite to each other to ensure that ions (e.g., lithium ions) can be transported between the negative electrode active material layer 230 and the positive electrode active material layer 130, thereby enabling the charging and discharging of the battery cell 10. Preferably, the negative electrode 200 can be made of copper foil. The negative electrode active material layer 230 can be made of graphite, carbon-like materials, carbon fibers, and other doped silicon-carbon, silicon-oxygen, or other negative electrode materials.

[0053] A separator 300 is disposed between the positive electrode 100 and the negative electrode 200 to completely isolate them, preventing direct contact and short circuits within the cell 10. Ions (e.g., lithium ions) can pass through the separator 300, ensuring transport between the negative active material layer 230 and the positive active material layer 130, thus enabling charging and discharging of the cell 10. A first coating layer 310 is provided on the side of the separator 300 near the positive electrode 100, filling the recess 121. It should be noted that the coating thickness of the first coating layer 310 on the separator 300 is thicker at the recess 121. At locations other than the recess 121 (i.e., locations without openings on the positive electrode 100), the coating thickness of the first coating layer 310 on the separator 300 is thinner. Preferably, the first coating layer 310 can be made of conventional coating materials such as PMMA (polymethyl methacrylate), PVDF (polyvinylidene fluoride), VGCF (vertical graphene resin composite), boehmite, or alumina. The first coating layer 310 allows for better wetting of the electrolyte. In particular, the use of PMMA (polymethyl methacrylate) for the first coating layer 310, due to its good swelling properties, allows the first coating layer 310 to more fully fill the recess 121, thereby improving the wetting effect of the electrolyte on the battery cell 10.

[0054] Specifically, in this embodiment, a recess 121 is provided in the positive active material layer 130 of the first corner segment 120 of the positive electrode 100, and the first coating layer 310 coated on the separator 300 is filled into the recess 121. Since the first coating layer 310 has good electrolyte absorption capacity, it can improve the wetting effect of the electrolyte on the positive electrode 100. The recessed hole 121 effectively creates a rapid lithium-ion transport channel, allowing lithium ions in the positive electrode active material layer 130 to be rapidly transported to the electrolyte, and then transported to the negative electrode active material layer 230 via the electrolyte. This enables the charging and discharging of the battery cell 10 and prevents lithium plating at the corners of the battery cell 10 due to concentrated lithium-ion transport (if lithium plating occurs at the corners of the battery cell 10, lithium dendrites will be generated, posing a risk that the lithium dendrites will pierce the separator 300, causing direct contact between the positive electrode 100 and the negative electrode 200, resulting in an internal short circuit). This ensures that the battery cell 10 will not experience an internal short circuit, eliminates the risk of thermal runaway of the battery cell 10, and improves the safety performance of the battery cell 10.

[0055] In addition, corresponding to the recess 121, the first coating layer 310 on the diaphragm 300 is thickened so that the first coating layer 310 can fully fill the recess 121 and compensate for the local stress unevenness caused by drilling holes in the positive electrode 100.

[0056] In some embodiments, refer to Figure 2 and Figure 4 The negative electrode active material layer 230 of the second corner segment 220 is provided with a first groove 221. For example, the first groove 221 can be formed in the negative electrode active material layer 230 of the second corner segment 220 by laser grooving. A second coating layer 320 is provided on the side of the separator 300 near the negative electrode plate 200, and the second coating layer 320 fills the first groove 221. It should be noted that the coating thickness of the second coating layer 320 on the separator 300 is thicker at the location corresponding to the first groove 221. The coating thickness of the second coating layer 320 on the separator 300 is thinner at the location not corresponding to the first groove 221 (i.e., the location on the negative electrode plate 200 without grooving). Preferably, the second coating layer 320 can be made of conventional coating materials such as PMMA (polymethyl methacrylate), PVDF (polyvinylidene fluoride), VGCF (vertical graphene resin composite), boehmite, alumina, etc. The second coating layer 320 can better wet the electrolyte. In particular, the second coating layer 320 is made of PMMA (polymethyl methacrylate), which has good swelling properties, allowing the second coating layer 320 to fill the first groove 221 more fully, thereby improving the wetting effect of the electrolyte on the battery cell 10. More preferably, a ceramic layer is coated between the separator 300 and the second coating layer 320.

[0057] Specifically, in this embodiment, a first groove 221 is formed in the negative electrode active material layer 230 of the second corner segment 220 of the negative electrode sheet 200, and the second coating layer 320 coated on the separator 300 is filled into the first groove 221. Since the second coating layer 320 has good electrolyte absorption capacity, it can improve the wetting effect of the electrolyte on the negative electrode sheet 200. The first groove 221 is equivalent to constructing a lithium ion fast transport channel, which enables the negative electrode active material layer 230 to quickly absorb the lithium ions transported in the electrolyte, effectively preventing lithium plating at the second corner segment 220, ensuring that the cell 10 will not experience internal short circuit, eliminating the risk of thermal runaway of the cell 10, and realizing normal charging and discharging of the cell 10.

[0058] Furthermore, referring to the above embodiment, the coating thickness of the first coating layer 310 on the separator 300 is thicker at the recess 121 of the positive electrode 100. The first groove 221 is opened in the second corner section 220 of the negative electrode 200, which can reduce the thickness of the negative electrode 200 at the second corner section 220, reduce the compressive stress of the second corner section 220, weaken the local expansion phenomenon caused by the filling of the coating layer on the separator 300, and reduce the risk of lithium plating in the corner section of the cell 10.

[0059] In some embodiments, refer to Figure 2 and Figure 4The negative electrode active material layer 230 of the second corner segment 220 is provided with a second groove 222, which is connected to the first groove 221. Along the direction from the diaphragm 300 to the negative electrode sheet 200, the projection of the second groove 222 onto the negative electrode sheet 200 overlaps the projection of the first groove 221 onto the negative electrode sheet 200. In other words, the first groove 221 and the second groove 222 form a stepped groove. The second coating layer 320 fills the second groove 222 and the first groove 221.

[0060] Specifically, in this embodiment, by forming a first groove 221 and a second groove 222 in the negative electrode active material layer 230 of the second corner segment 220, and filling both the first groove 221 and the second groove 222 with a second coating layer 320, the above structure helps to extend the lithium ion transport path and prevent lithium ion aggregation and lithium plating. Furthermore, since the projection of the second groove 222 onto the negative electrode sheet 200 overlaps the projection of the first groove 221 onto the negative electrode sheet 200, i.e., the groove area of ​​the second groove 222 is larger than the groove area of ​​the first groove 221, a gradient edge is formed between the second groove 222 and the first groove 221. This gradient edge helps to increase the absorption area of ​​the negative electrode active material layer 230 for lithium ions, improves the absorption efficiency of the negative electrode active material layer 230 for lithium ions, effectively prevents lithium plating on the negative electrode sheet 200, and ensures the safety of the battery cell 10.

[0061] In some embodiments, the first groove 221 and the second groove 222 can be rectangular grooves, circular grooves, etc., and the structural shape of the first groove 221 and the second groove 222 is not limited in a single way.

[0062] In some embodiments, refer to Figure 3 and Figure 4 The length L1 of the first straight segment 110 and the length L2 of the first corner segment 120 satisfy the condition: L1 > 1.5L2. The length L3 of the second straight segment 210 and the length L4 of the second corner segment 220 satisfy the condition: L3 > 1.5L4. For example, the value of L1 can be 2L2, 2.5L2, 3L2, 3.5L2, etc. The value of L3 can be 2L4, 2.5L4, 3L4, 3.5L4, etc.

[0063] Specifically, in this embodiment, compared to the transport of lithium ions between the first corner segment 120 and the second corner segment 220, lithium ions are less likely to accumulate at a certain position when transported between the first straight segment 110 and the second straight segment 210. Therefore, lithium ion deposition is less likely to occur when lithium ions are transported between the first straight segment 110 and the second straight segment 210. Thus, designing the length of the first straight segment 110 to be longer than the length of the first corner segment 120, and designing the length of the second straight segment 210 to be longer than the length of the second corner segment 220, can effectively reduce the risk of lithium deposition inside the battery cell 10.

[0064] In some embodiments, refer to Figure 2 and Figure 4 The length L5 of the first groove 221 satisfies: 0.8L4 ≤ L5 ≤ 1.2L4, and the groove depth D1 of the first groove 221 satisfies: 5µm ≤ D1 ≤ 20µm. For example, the value of L5 can be 0.8L4, L4, 1.2L4, etc. The value of D1 can be 5µm, 10µm, 15µm, 20µm, etc. The length L6 of the second groove 222 satisfies: L4 ≤ L6 ≤ 1.4L4, and the groove depth D2 of the second groove 222 satisfies: 20µm ≤ D2 ≤ 50µm. For example, the value of L6 can be L4, 1.2L4, 1.4L4, etc. The value of D2 can be 20µm, 30µm, 40µm, 50µm, etc.

[0065] Specifically, in this embodiment, the length and depth of the first groove 221 are set within the aforementioned range, which is beneficial for improving the wetting effect of the electrolyte on the negative electrode sheet 200, and also avoids excessive loss of the negative electrode active material layer 230 due to excessively large groove area. If the length of the first groove 221 is too short (for example, the length L5 of the first groove 221 is less than 0.8L4), or the depth of the first groove 221 is too shallow (for example, the depth D1 of the first groove 221 is less than 5µm), then the volume of the second coating layer 320 filling the first groove 221 will be too small, which is not conducive to improving the wetting effect of the electrolyte on the negative electrode sheet 200. If the length of the first groove 221 is too long (for example, the length L5 of the first groove 221 is greater than 1.2L4), or the groove depth of the first groove 221 is too deep (for example, the groove depth D1 of the first groove 221 is greater than 20µm), then the opening area of ​​the first groove 221 is too large, resulting in excessive loss of the negative electrode active material layer 230, which is not conducive to improving the energy density of the cell 10.

[0066] Similarly, setting the length and depth of the second groove 222 within the aforementioned range is beneficial for improving the wetting effect of the electrolyte on the negative electrode 200, while also preventing excessive loss of the negative electrode active material layer 230 due to an excessively large groove area. If the length of the second groove 222 is too short (e.g., the length L6 of the second groove 222 is less than L4), or the depth of the second groove 222 is too shallow (e.g., the depth D2 of the second groove 222 is less than 20µm), then the volume of the second coating layer 320 filling the second groove 222 will be too small, which is not conducive to improving the wetting effect of the electrolyte on the negative electrode 200. If the length of the second groove 222 is too long (for example, the length L6 of the second groove 222 is greater than 1.4L4), or the groove depth of the second groove 222 is too deep (for example, the groove depth D2 of the second groove 222 is greater than 50µm), then the opening area of ​​the second groove 222 is too large, resulting in excessive loss of the negative electrode active material layer 230, which is not conducive to improving the energy density of the cell 10.

[0067] In addition, the length of the first groove 221 is less than the length of the second groove 222, so that a stepped groove is formed between the first groove 221 and the second groove 222. The gradient stepped surface between the first groove 221 and the second groove 222 is conducive to increasing the contact area with lithium ions, thereby improving the absorption capacity of lithium ions, preventing lithium plating, and ensuring the safety of the battery cell 10.

[0068] In some embodiments, refer to Figure 2 and Figure 3 The diameter φ of the concave hole 121 satisfies: 100µm ≤ φ ≤ 500µm; the depth D3 of the concave hole 121 satisfies: 5µm ≤ D3 ≤ 80µm. For example, the value of φ can be 100µm, 200µm, 300µm, 400µm, 500µm, etc. The value of D3 can be 5µm, 10µm, 30µm, 60µm, 80µm, etc.

[0069] Specifically, in this embodiment, the aperture and depth of the recessed hole 121 are set within the aforementioned range, which is beneficial for improving the wetting effect of the electrolyte on the positive electrode 100 and avoids excessive loss of the positive electrode active material layer 130 due to excessively large opening area. If the aperture of the recessed hole 121 is too small (for example, the aperture φ of the recessed hole 121 is less than 100µm), or the depth of the recessed hole 121 is too shallow (for example, the depth D3 of the recessed hole 121 is less than 5µm), then the volume of the first coating layer 310 filling the recessed hole 121 will be too small, which is not conducive to improving the wetting effect of the electrolyte on the positive electrode 100. If the aperture of the recess 121 is too large (e.g., the aperture φ of the recess 121 is greater than 500µm), or the depth of the recess 121 is too deep (e.g., the depth D3 of the recess 121 is greater than 80µm), the opening area of ​​the recess 121 will be too large, resulting in excessive loss of the positive electrode active material layer 130, which is not conducive to improving the energy density of the cell 10.

[0070] In some embodiments, refer to Figure 2 and Figure 5 The coating thickness D4 of the first coating layer 310 at the first straight section 110 satisfies: 0.5µm ≤ D4 ≤ 6µm, and the coating thickness D5 of the first coating layer 310 at the first corner section 120 satisfies: 10µm ≤ D5 ≤ 50µm. For example, the value of D4 can be 0.5µm, 2µm, 4µm, 6µm, etc. The value of D5 can be 10µm, 20µm, 30µm, 40µm, 50µm, etc. The coating thickness D6 of the second coating layer 320 at the second straight section 210 satisfies: 0.5µm ≤ D6 ≤ 6µm, and the coating thickness D7 of the second coating layer 320 at the second corner section 220 satisfies: 10µm ≤ D7 ≤ 50µm. For example, the value of D6 can be 0.5µm, 2µm, 4µm, 6µm, etc. The value of D7 can be 10µm, 20µm, 30µm, 40µm, 50µm, etc.

[0071] Specifically, in this embodiment, since the first straight section 110 does not have a recessed hole 121 structure, the thickness of the first coating layer 310 on the separator 300 corresponding to the first straight section 110 is relatively thin. Since the first corner section 120 has a recessed hole 121 structure, the first coating layer 310 needs to fill the recessed hole 121 to eliminate local stress unevenness at the recessed hole 121; therefore, the thickness of the first coating layer 310 on the separator 300 corresponding to the first corner section 120 is relatively thick. Furthermore, setting the coating thickness of the first coating layer 310 on the first straight section 110 and on the first corner section 120 within the aforementioned range is beneficial for improving the adsorption capacity of the electrolyte and also avoids the overall thickness of the battery cell 10 being too thick. If the coating thickness of the first coating layer 310 is too thin, it will be detrimental to improving the adsorption capacity of the first coating layer 310 for the electrolyte, thereby reducing the wetting effect of the electrolyte on the positive electrode 100. If the coating thickness of the first coating layer 310 is too thick, it will result in a larger overall thickness of the battery cell 10, thereby reducing the energy density of the battery cell 10.

[0072] Similarly, since the second straight section 210 lacks the first groove 221 and the second groove 222, the thickness of the second coating layer 320 on the diaphragm 300 corresponding to the second straight section 210 is relatively thin. Since the second corner section 220 has the first groove 221 and the second groove 222, the second coating layer 320 needs to fill the first groove 221 and the second groove 222 to eliminate localized stress unevenness at the first groove 221 and the second groove 222. Therefore, the thickness of the second coating layer 320 on the diaphragm 300 corresponding to the second corner section 220 is relatively thick. Furthermore, setting the coating thickness of the second coating layer 320 on the second straight section 210 and on the second corner section 220 within the aforementioned range is beneficial for improving the electrolyte adsorption capacity and also avoids excessive overall thickness of the battery cell 10. If the coating thickness of the second coating layer 320 is too thin, it will not be conducive to improving the adsorption capacity of the second coating layer 320 for the electrolyte, thereby reducing the wetting effect of the electrolyte on the negative electrode plate 200. If the coating thickness of the second coating layer 320 is too thick, it will result in a larger overall thickness of the battery cell 10, thereby reducing the energy density of the battery cell 10.

[0073] In some embodiments, the total thickness X1 of the diaphragm 300 at the first corner segment 120 and the second corner segment 220 satisfies: 0.8(X2+X3)≤X1≤(X2+X3). Wherein, X2 is the maximum hole depth of the concave hole 121, and X3 is the maximum value of the sum of the groove depths of the first groove 221 and the second groove 222.

[0074] Specifically, in this embodiment, the total thickness of the separator 300 at the first corner segment 120 and the second corner segment 220 is set within the aforementioned range. On the one hand, this prevents the total thickness of the separator 300 at the first corner segment 120 and the second corner segment 220 from being too thin, which would result in the separator 300 (specifically, the first coating layer 310 and the second coating layer 320 on the separator 300) not being able to effectively fill the recess 121 of the first corner segment 120 and the groove of the second corner segment 220, thus hindering the improvement of the electrolyte's wetting effect on the positive electrode 100 and the negative electrode 200. Moreover, if the recess 121 of the first corner segment 120 and the groove of the second corner segment 220 cannot be effectively filled by the separator 300, it will lead to uneven local stress in the first corner segment 120 and the second corner segment 220, affecting the safety of the battery cell 10. On the other hand, to prevent the total thickness of the separator 300 at the first corner section 120 and the second corner section 220 from being too thick, which would cause local expansion of the first corner section 120 and the second corner section 220, local expansion would compress the positive electrode 100, the negative electrode 200 and the separator 300, affecting the normal transport of lithium ions and reducing the capacity and discharge rate of the cell 10.

[0075] Correspondingly, another embodiment of this utility model also provides a battery, which includes the cell 10 in any of the above embodiments. The battery also includes an aluminum-plastic film shell, in which the cell 10 is encapsulated. An adhesive layer may be provided between the cell 10 and the aluminum-plastic film shell to improve the encapsulation stability of the cell 10 within the aluminum-plastic film shell and prevent the cell 10 from shaking within the aluminum-plastic film shell, thus affecting the safety of battery use.

[0076] Specifically, in this embodiment, the electrolyte in the cell 10 has a good wetting effect, which is beneficial to the transport of lithium ions inside the cell 10. Batteries using the cell 10 described above can prevent lithium plating inside the battery, thereby reducing the risk of thermal runaway and ensuring battery safety.

[0077] Correspondingly, one embodiment of this utility model also provides an electronic device, which includes the battery described in the above embodiments. This electronic device can be a mobile phone, tablet, laptop, etc.

[0078] Specifically, in this embodiment, the electronic device using the above-mentioned battery can ensure safe use.

[0079] Thanks to the improvements to the battery cell 10 described above, the battery and electronic device of this embodiment have the same technical effects as the battery cell 10 described above, which will not be repeated here.

[0080] It should be noted that other contents of the battery cell 10, battery and electronic equipment disclosed in this utility model can be found in the prior art, and will not be repeated here.

[0081] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. An electric cell, characterized by, Comprising: a positive electrode tab, the positive electrode tab comprising a first flat section and a first corner section, the first corner section being connected to one end of the first flat section, surfaces of the first flat section and the first corner section are both coated with a positive electrode active material layer, the positive electrode active material layer of the first corner section is provided with a recess hole; a negative electrode tab, the negative electrode tab comprising a second flat section and a second corner section, the second corner section being connected to one end of the second flat section, the second flat section and the first flat section are oppositely arranged, the second corner section and the first corner section are oppositely arranged, surfaces of the second flat section and the second corner section are both coated with a negative electrode active material layer; a separator, the separator being arranged between the positive electrode tab and the negative electrode tab, one side of the separator close to the positive electrode tab is provided with a first coating layer, the first coating layer fills into the recess hole.

2. The electric cell of claim 1, wherein, The negative electrode active material layer of the second corner section is provided with a first groove, one side of the separator close to the negative electrode tab is provided with a second coating layer, the second coating layer fills into the first groove.

3. The electric cell of claim 2, wherein, The negative electrode active material layer of the second corner section is provided with a second groove, the second groove and the first groove are communicated, in the direction from the separator to the negative electrode tab, the projection of the second groove on the negative electrode tab covers the projection of the first groove on the negative electrode tab; wherein the second coating layer fills into the second groove and the first groove.

4. The electric cell of claim 3, wherein, The length L1 of the first flat section and the length L2 of the first corner section satisfy: L1>1.5L2; The length L3 of the second flat section and the length L4 of the second corner section satisfy: L3>1.5L4.

5. The electric cell of claim 4, wherein, The length L5 of the first groove satisfies: 0.8L4≤L5≤1.2L4, the groove depth D1 of the first groove satisfies: 5µm≤D1≤20µm; The length L6 of the second groove satisfies: L4≤L6≤1.4L4, the groove depth D2 of the second groove satisfies: 20µm≤D2≤50µm.

6. The electric cell of claim 1, wherein, The aperture diameter φ of the recess hole satisfies: 100µm≤φ≤500µm; the hole depth D3 of the recess hole satisfies: 5µm≤D3≤80µm.

7. The electric cell of claim 2, wherein, The coating thickness D4 of the first coating layer at the first flat section satisfies: 0.5µm≤D4≤6µm, the coating thickness D5 of the first coating layer at the first corner section satisfies: 10µm≤D5≤50µm; The coating thickness D6 of the second coating layer at the second flat section satisfies: 0.5µm≤D6≤6µm, the coating thickness D7 of the second coating layer at the second corner section satisfies: 10µm≤D7≤50µm.

8. The electric cell of claim 3, wherein, The total thickness X1 of the separator at the first corner section and the second corner section satisfies: 0.8(X2+X3)≤X1≤(X2+X3); wherein X2 is the maximum hole depth of the recess hole, X3 is the maximum value of the sum of the groove depths of the first groove and the second groove.

9. A battery characterized by Comprising: the battery cell of any one of claims 1 to 8; a shell, the battery cell being packaged in the shell.

10. An electronic device, characterized by The battery of claim 9.

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