Battery cell and corner pressing seal head

Abstract

The utility model discloses a battery cell and a corner pressing seal head, which are applied to the technical field of batteries and comprise a battery cell body and a shell covering the battery cell body, the shell comprises a membrane shell for accommodating the battery cell body, and the membrane shell is provided with a bottom corner part; the shell is provided with a corner pressing structure, the corner pressing structure comprises an R corner part and a convex part, and a clearance part is formed between the convex part and the R corner part; the R corner part is arranged along one part of the edge of the bottom corner part, and the clearance part extends to the other part of the edge of the bottom corner part. The receding part is formed in the corner pressing structure, excessive extrusion of the protruding part on the membrane shell can be avoided, and therefore allowance is reserved for deformation of the membrane shell in the follow-up using process, and the corner breakage probability of the bottom corner of the membrane shell is reduced.

Description

Technical Field

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

[0002] With the continuous advancement of science and technology, people hope that electronic products will be lighter and more compact, which puts higher requirements on the energy density of battery cells. In the process of pursuing energy density, in addition to continuously improving the gram capacity of the main material, the thickness of the auxiliary material is continuously reduced, compressing the volume of the membrane shell, and reducing the gap between the core and the membrane shell are also important ways and means.

[0003] However, in the process of reducing the volume of the winding core / membrane shell, it is found that the electrode will have a certain proportion of extension in the three directions of X / Y / Z. The extension of the electrode itself will interfere with the membrane shell. During the cycle, the breathing effect squeezes the membrane shell. According to the tensile stress and strain principle of metals, when the tensile stress / strain of the aluminum-plastic film passes through the plastic deformation stage and reaches the peak of the tensile strength, it will break and the battery cell corner will be broken, which will create a safety risk on the user side.

[0004] During the analysis of corner breakage, it is found that the ratio of bottom corner breakage is much higher than that of top corner breakage. Therefore, how to provide a battery cell that can reduce the ratio of bottom corner breakage is an urgent problem that technicians in this field need to solve. Utility Model Content

[0005] The purpose of the present invention is to provide a battery cell with a low probability of bottom corner breakage; another purpose of the present invention is to provide a corner pressing head that can reduce the probability of bottom corner breakage of the battery cell.

[0006] In order to solve the above technical problems, the present invention provides a battery cell, comprising a battery cell body and a shell covering the battery cell body; the shell comprises a membrane shell accommodating the battery cell body, and the membrane shell has a bottom corner portion;

[0007] The housing is provided with a pressure angle structure, the pressure angle structure includes an R corner portion and a convex portion, and a space-avoiding portion is formed between the convex portion and the R corner portion;

[0008] The R-corner portion is provided along a portion of the edge of the bottom corner portion, and the avoidance portion extends to another portion of the edge of the bottom corner portion.

[0009] Optionally, the R angle of the R corner portion is greater than the R angle of the bottom corner portion.

[0010] Optionally, the housing further comprises a sealing area located outside the membrane shell, and an inner unsealed area located between the membrane shell and the sealing area;

[0011] The air-avoiding portion is arranged in the inner unsealed area.

[0012] Optionally, the width of the R corner portion ranges from 0.3 mm to 2 mm, the R angle size of the R corner portion ranges from 1.5 mm to 2.5 mm, and the width of the air avoidance portion ranges from 0 mm to 3 mm.

[0013] Optionally, there is a back margin between the bottom corner portion and the back of the shell, and the back margin is not less than 1.4 mm.

[0014] Optionally, the back margin has a value range of 1.4 mm to 4.0 mm.

[0015] Optionally, the battery cell body includes a positive electrode sheet and a negative electrode sheet, the negative electrode sheet includes a negative electrode current collector and a negative electrode paste layer, and the negative electrode paste layer is a graphite paste layer or a silicon-based material paste layer or a mixed paste layer of graphite and silicon-based materials.

[0016] Optionally, the absolute strength of the negative electrode current collector ranges from 450 N / m to 1000 N / m.

[0017] Optionally, the thickness of the negative electrode current collector ranges from 1 μm to 15 μm.

[0018] The present invention also provides a corner pressing head for forming a corner pressing structure in a battery cell as described in any one of the above items, comprising:

[0019] A corner pressing body, a corner pressing R corner portion located on one side edge of the corner pressing body, and a corner pressing convex portion protruding from one side edge of the corner pressing body; the corner pressing convex portion is arranged close to one end portion of the corner pressing R corner portion, and a preset interval is arranged between the corner pressing convex portion and one end portion of the corner pressing R corner portion to form a corner pressing avoidance portion.

[0020] The utility model provides a battery cell, comprising a battery cell body and a shell covering the battery cell body; the shell comprises a membrane shell for accommodating the battery cell body, and the membrane shell has a bottom corner portion; the shell is provided with a pressure angle structure, and the pressure angle structure comprises an R corner portion and a convex portion, and a gap is formed between the convex portion and the R corner portion; the R corner portion is provided along a portion of the edge of the bottom corner portion, and the gap extends to another portion of the edge of the bottom corner portion.

[0021] Forming a clearance portion in the angle-pressing structure can prevent the convex portion from excessively squeezing the membrane shell, thereby leaving a margin for deformation of the membrane shell during subsequent use, thereby reducing the probability of breakage of the bottom corner of the membrane shell.

[0022] The present invention also provides a corner pressing head, which can also achieve the above-mentioned beneficial effects and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 It is a schematic diagram of the local structure of a battery cell in the prior art;

[0025] Figure 2 and Figure 3 This is an electron microscope scanning image of a battery cell provided by an embodiment of the present utility model;

[0026] Figure 4 A schematic diagram of the overall structure of a battery cell provided by an embodiment of the present utility model;

[0027] Figure 5 This is a schematic structural diagram of a specific battery cell provided by an embodiment of the present utility model.

[0028] In the figure: 1. membrane shell, 11. bottom corner, 21. R corner, 22. protrusion, 23. airtight part, 3. inner unsealed area, 4. sealing area, 5. battery cell body. DETAILED DESCRIPTION

[0029] The core of this utility model is to provide a battery core. Figure 1 , Figure 1 This is a schematic diagram of the partial structure of a battery cell in the prior art. Figure 1 In the prior art, the outer shell of a battery cell is typically formed by first pressing two recesses into a piece of material, then folding it in half and sealing the edges. The two recesses align to form a membrane shell 1, and the corner of the membrane shell 1 facing the folded position is the bottom corner 11. Because the bottom corner 11 is not fully folded, it will require manual inspection of the appearance. This process requires an additional corner pressing step next to the bottom corner 11, forming a corner pressing structure. If the corner pressing extends too far into the shell volume, it will interfere with the membrane shell space, affecting the membrane shell space expansion, and thus increasing the probability of the bottom corner breaking.

[0030] The utility model provides a battery cell, including a battery cell body and a shell covering the battery cell body; the shell includes a membrane shell for accommodating the battery cell body, and the membrane shell has a bottom corner portion; the shell is provided with a pressure angle structure, and the pressure angle structure includes an R corner portion and a convex portion, and a gap is formed between the convex portion and the R corner portion; the R corner portion is provided along a portion of the edge of the bottom corner portion, and the gap extends to another portion of the edge of the bottom corner portion.

[0031] Forming a clearance portion in the angle-pressing structure can prevent the convex portion from excessively squeezing the membrane shell, thereby leaving a margin for deformation of the membrane shell during subsequent use, thereby reducing the probability of breakage of the bottom corner of the membrane shell.

[0032] To help those skilled in the art better understand the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments described are only a portion of the present invention, not all of the embodiments. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0033] Example 1

[0034] Please refer to Figures 2 to 5 , Figure 2 and Figure 3 This is an electron microscope scanning image of a battery cell provided by an embodiment of the present utility model; Figure 4 A schematic diagram of the overall structure of a battery cell provided by an embodiment of the present utility model; Figure 5 This is a schematic structural diagram of a specific battery cell provided by an embodiment of the present utility model.

[0035] See also Figure 2 as well as Figure 3 In an embodiment of the utility model, the battery cell includes a battery cell body 5 and a shell covering the battery cell body 5; the shell includes a membrane shell 1 for accommodating the battery cell body 5, and the membrane shell 1 has a bottom corner portion 11; the shell is provided with a pressure angle structure, and the pressure angle structure includes an R corner portion 21 and a convex portion 22, and a gap 23 is formed between the convex portion 22 and the R corner portion 21; the R corner portion 21 is provided along a portion of the edge of the bottom corner portion 11, and the gap 23 extends to another portion of the edge of the bottom corner portion 11.

[0036] The above-mentioned battery cell body 5 is a structure in which the battery cell is mainly used for power generation. The specific content will be described in detail in the following utility model embodiments and will not be repeated here. The above-mentioned shell will wrap the battery cell body 5, and the shell is formed with a membrane shell 1. The space formed by the membrane shell 1 is used to accommodate the battery cell body 5. Since the shell is formed by folding in half and then sealing the edges, the membrane shell 1 is composed of two pits that are combined after folding in half. In this embodiment, the cross-section of the above-mentioned membrane shell 1 along the thickness direction is usually a rounded rectangle, and one side of the corresponding membrane shell 1 faces the bending position of the shell, and the other three sides face the sealing position of the shell, that is, the above-mentioned sealing process is usually to seal the three non-bending edges of the shell to form the above-mentioned shell.

[0037] See also Figure 4 , the above Figure 1 as well as Figure 2 for Figure 4An enlarged view of the circled area A is shown. Accordingly, in this embodiment, in addition to the membrane shell 1, the housing also includes a sealed area 4 located outside the membrane shell 1 and an inner unsealed area located between the membrane shell 1 and the sealed area 4. That is, in this embodiment, the housing, from the center toward the sealed edge, is sequentially provided with the membrane shell 1, the inner unsealed area 3, and the sealed area 4; and from the center toward the bent edge, the housing is sequentially provided with the membrane shell 1 and the inner unsealed area 3.

[0038] In this embodiment, the corner of the membrane shell 1 facing the bent edge is the bottom corner 11, and a pressing structure is formed in the shell based on the pressing process. The pressing structure is arranged adjacent to the bottom corner 11. The morphology of the pressing structure is specifically corresponding to the morphology of the pressing head used in the pressing process. In this embodiment, the pressing head usually has a pressing convex portion and a pressing angle R corner portion, wherein the pressing convex portion is arranged near one end of the pressing angle R corner portion, and the pressing convex portion is arranged adjacent to the pressing angle R corner portion. There is a gap between the parts to form a pressure angle avoidance part. Correspondingly, in this embodiment, based on the above-mentioned pressure angle head, a pressure angle structure including an R-corner part 21, a convex part 22 and a avoidance part 23 will be formed on the shell, wherein the head part 22 of the pressure angle structure corresponds to the pressure angle convex part of the pressure angle head, the R-corner part 21 of the pressure angle structure corresponds to the pressure angle R-corner part of the pressure angle head, and the avoidance part 23 of the pressure angle structure corresponds to the pressure angle avoidance part of the pressure angle head. The above-mentioned avoidance part 23 is located between the R-corner part 21 of the pressure angle structure and its convex part 22.

[0039] In this embodiment, the R-shaped corner portion 21 of the angle-pressing structure is disposed along a portion of the edge of the bottom corner portion 11 of the membrane shell 1, and the aforementioned avoidance portion 23 extends to another portion of the edge of the bottom corner portion 11. That is, during the angle-pressing process, the R-shaped corner portion of the angle-pressing seal will be tangent to the bottom corner portion 11 of the membrane shell 1, and accordingly, the R-shaped corner portion 21 of the angle-pressing structure will be disposed along a portion of the edge of the bottom corner portion 11, and the edge of the R-shaped corner portion 21 will be tangent to a portion of the edge of the bottom corner portion 11. In this embodiment, the R-shaped corner portion 21 is not disposed along the entire edge of the bottom corner portion 11, but only along a portion of the edge, and the aforementioned avoidance portion 23 is formed on the outside of the other portion of the edge of the bottom corner portion 11.

[0040] In this embodiment, the avoidance portion 23 is a structure formed in the shell that is not pressed by the corner pressure head. Since the avoidance portion 23 extends to a part of the edge of the bottom corner portion 11 in this embodiment, the corner pressure structure does not affect the morphology of the membrane shell 1 too much, and the avoidance portion 23 can be used as a reserved space for the bottom corner portion 11 to expand outward. Based on the setting of the avoidance portion 23, the probability of the bottom corner of the membrane shell 1 being broken can be effectively reduced.

[0041] Specifically, the R angle size of the R corner portion 21 usually needs to be larger than the R angle size of the bottom corner portion 11. At this time, it can be ensured that the R corner portion 21 of the corner pressing head cannot completely cover the edge of the entire bottom corner portion 11 during the corner pressing process, but a part of the space between the R corner portion 21 and the bottom corner portion 11 will inevitably be left to form an escape portion 23 to reduce the probability of the bottom corner of the membrane shell 1 being broken. Of course, in this embodiment, the R angle size of the above-mentioned R corner portion 21 can also be equal to the R angle size of the bottom corner portion 11, but at this time, the length of the R corner portion 21 along the edge of the membrane shell 1 needs to be less than the length of the edge of the bottom corner portion 11, so that part of the edge of the bottom corner portion 11 can be reserved to be adjacent to the escape portion 23.

[0042] In this embodiment, the avoidance portion 23 is usually provided in the inner unsealed area 3. Of course, the avoidance portion 23 may also extend from the inner unsealed area 3 to the sealed area 4. The size of the avoidance portion 23 is usually determined by the position of the protrusion 22. When the protrusion 22 is provided in the sealed area 4, the avoidance portion 23 will extend from the inner unsealed area 3 to the sealed area 4. When the protrusion 22 is provided along the edge of the sealed area 4 and the inner unsealed area 3 or extends into the inner unsealed area 3, the avoidance portion 23 will only be provided in the inner unsealed area 3.

[0043] In this embodiment, the width of the R corner portion 21 is in the range of 0.3mm to 2mm, the R angle of the R corner portion 21 is in the range of 1.5mm to 2.5mm, and the width of the gap portion 23 is in the range of 0mm to 3mm. Figure 4 As shown, assuming that the width of the R corner portion 21 is d, the R angle of the R corner portion 21 is e, and the width of the gap portion 23 is f, there exists 2mm≥d≥0.3mm, 2.5mm≥e≥1.5mm, and 3mm≥f≥0mm.

[0044] The above-mentioned d, e, and f are the dimensional parameters of the corner-pressing structure, which together determine the corner-pressing volume. The larger the corner-pressing volume, the greater the interference volume with the core after expansion. This will continuously interfere with the core during circulation, ultimately leading to corner breakage. When the dimensional parameters d, e, and f of the corner-pressing structure are within the above-mentioned ranges, the probability of corner breakage at the bottom corner of the membrane shell 1 can be significantly reduced. Of course, in this embodiment, the specific dimensions of the above-mentioned corner-pressing structure are not specifically limited and will be determined based on the specific circumstances.

[0045] The battery cell provided in this embodiment forms a void portion 23 in the corner pressing structure, which can prevent the convex portion 22 from excessively squeezing the membrane shell 1, thereby leaving a margin for deformation of the membrane shell 1 during subsequent use, thereby reducing the probability of breakage of the bottom corner of the membrane shell 1.

[0046] The specific structure of a battery cell provided by the present invention will be described in detail in the following embodiments of the present invention and will not be described in detail here.

[0047] Example 2

[0048] Different from the above embodiment, this embodiment further defines the specific structure of the battery cell based on the above embodiment. The rest of the content has been described in detail in the above utility model embodiment and will not be repeated here.

[0049] See also Figure 4 In this embodiment, there is a back margin between the bottom corner portion 11 and the back of the shell, and the back margin is not less than 1.4 mm. The above-mentioned back margin is the distance between the side of the membrane shell 1 facing the bending position of the shell and the bending position of the shell. When the back margin is small, stress concentration is easily formed, resulting in an increased probability of bottom corner breakage. In this embodiment, stress concentration can be avoided and the probability of bottom corner breakage can be reduced by increasing the above-mentioned back margin. In this embodiment, the above-mentioned back margin is usually not less than 1.4 mm to ensure that the shell has sufficient back margin to avoid stress concentration. Specifically, in this embodiment, the value range of the back margin is between 1.4 mm and 4.0 mm. That is, if the back margin is g, it is usually necessary to meet the requirement that g is between 1.4 mm and 4.0 mm.

[0050] In this embodiment, the battery cell body 5 generally includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet generally includes a positive electrode current collector and a positive electrode paste layer. The negative electrode sheet includes a negative electrode current collector and a negative electrode paste layer. The negative electrode paste layer is a graphite paste layer or a silicon-based material paste layer or a mixed paste layer of graphite and silicon-based materials.

[0051] Specifically, in this embodiment, the absolute strength of the negative electrode current collector is generally in the range of 450 N / m to 1000 N / m, preferably 450 N / m to 700 N / m. The thickness of the negative electrode current collector is generally in the range of 1 μm to 15 μm, preferably 3 μm to 7 μm. In this embodiment, the silicon-based material paste layer contains the general formula M y SiO x One or more silicon-oxygen materials in the components represented by , where 0 ≤ y ≤ 4, 0 ≤ x ≤ 4, and M is at least one of Li, Mg, Ti, and Al. The weight ratio of the silicon-based material is typically 0% to 20% based on the total weight of the negative electrode paste layer. Assuming the OI value of the graphite in the negative electrode paste layer is a, the copper foil strength is b N / m, and the copper foil thickness is c μm, the above values ​​are typically within the following ranges:

[0052] 30≥a≥8, 700 N / m≥b≥450 N / m, 7μm≥c≥3μm.

[0053] In this embodiment, the smaller the graphite OI value a, the greater the electrode extension and the higher the risk of corner breakage; the smaller the copper foil strength, the greater the electrode extension and the higher the risk of corner breakage. When these parameters are set within the above range, the probability of corner breakage at the bottom corner of the membrane shell 1 can be significantly reduced.

[0054] In this embodiment, the above-mentioned negative electrode paste layer is mainly artificial graphite, natural graphite, mesophase carbon microbeads, soft carbon, hard carbon, organic polymer compound carbon, lithium titanate, silicon oxide, silicon carbon, or any one or a combination of two or more thereof; and the positive electrode paste layer can be one or a combination of lithium cobalt oxide, ternary material, lithium iron phosphate, lithium manganese oxide, and lithium titanate.

[0055] The preparation method of the battery cell provided in this embodiment is as follows:

[0056] The first step is to prepare a coating slurry: a mixture of artificial graphite and silicon carbon is used as the negative electrode active material; conductive carbon black is used as the conductive agent, styrene-butadiene rubber is used as the binder, and sodium carboxymethyl cellulose is used as the thickener. The negative electrode active material: conductive agent: binder: thickener are added into a stirring tank in a mass ratio of 96.9:1.5:1.3:13, deionized water solvent is added, and the mixture is fully stirred according to the batching process of the prior art. The mixture is filtered through a 150-mesh sieve to prepare a slurry with a solid content of 40% to 45%.

[0057] The second step is negative electrode coating and sheeting: use a coating machine to coat the above-mentioned negative electrode slurry on the copper foil current collector, dry it at 100°C to prepare the initial negative electrode sheet; cut the above-mentioned initial sheet according to actual needs to prepare the negative electrode sheet.

[0058] The third step is to prepare the positive electrode slurry: lithium cobalt oxide is used as the positive electrode active material, and then added into a stirring tank with a conductive agent and polyvinylidene fluoride in a mass ratio of 97.2:1.5:1.3, and NMP (N-methylpyrrolidone) solvent is added for thorough stirring. After passing through a 200-mesh sieve, the positive electrode slurry is prepared. The solid content of the positive electrode slurry is 70% to 75%.

[0059] The fourth step is positive electrode coating and sheeting: the positive electrode slurry is coated on the aluminum foil current collector using a coating machine, and dried at 120°C to prepare the initial positive electrode sheet; the initial sheet is cut according to actual needs to prepare the positive electrode sheet.

[0060] Step 5: Assembling the battery cell: The positive and negative electrodes, along with the separator, are wound together to form a core, which is then wrapped in aluminum-plastic film. After baking to remove moisture, the electrolyte is injected and hot-pressed to form the battery cell. The aluminum-plastic film will form the casing.

[0061] The test methods corresponding to the above parameters are as follows:

[0062] OI value testing method: The OI value of the negative electrode active material powder and the OI value of the negative electrode paste layer can be obtained using an X-ray powder diffractometer. According to the general rules of X-ray diffraction analysis and the method for determining the lattice parameters of graphite (JIS K0131-1996 and JB / T4220-2011), an X-ray diffraction pattern is obtained. OI value = C004 / C110, where C004 is the peak area of ​​the 004 characteristic diffraction peak and C110 is the peak area of ​​the 110 characteristic diffraction peak. Specifically, the OI value of the negative electrode active material powder is tested by placing a certain mass of the negative electrode active material powder in an X-ray powder diffractometer and obtaining the peak area of ​​the 004 crystal plane diffraction peak and the peak area of ​​the 110 crystal plane diffraction peak by X-ray diffraction analysis, thereby obtaining the powder OI value of the negative electrode active material particles. Specifically, the OI value test method of the negative electrode paste layer is: directly placing the prepared negative electrode plate into an X-ray powder diffractometer, and obtaining the peak area of ​​the 004 crystal plane diffraction peak and the peak area of ​​the 110 crystal plane diffraction peak by X-ray diffraction analysis, and then obtaining the OI value of the negative electrode paste layer.

[0063] Copper foil strength and thickness test method: Use a tensile testing machine with a range of 0N to 1000N and an indication error of ±1%, and a vernier caliper with a range of 0mm to 300mm and a minimum graduation of 0.02mm, or other measuring instruments of comparable accuracy. Cut a sample of 200±0.5mm in length and 15±0.25mm in width from the object to be tested. Take two samples longitudinally and transversely across the width of the object to be tested. Then, place the sample in a tensile testing machine with a chuck distance of 125±0.1mm, a chuck extension speed of 50mm / min, and a test temperature of 20±10°C. Continuously apply load to the sample in the longitudinal direction until it breaks. Read the maximum load F from the force gauge or tensile curve, and calculate the absolute strength: σ = F / L, where L is the width of the sample to be tested. Take the arithmetic average of the test results for 3-5 samples to determine the absolute strength of the object to be tested.

[0064] Elongation test method: disassemble the electrode in the fully charged state, test the electrode width a and record it. The designed electrode width is a0, and the elongation = (a-a0) / a0*100%.

[0065] 45℃-1000T test method: According to the charge and discharge method in the battery specification, the battery cell is tested for 1000 cycles in an environment of 45℃±2.

[0066] Method for measuring the size of the angle-pressing structure: magnify the local area under a 2.5D microscope and measure the size parameters of the angle-pressing structure by taking dot-dash lines.

[0067] Example 3

[0068] The following is an introduction to a corner pressing head provided in an embodiment of the present invention. The corner pressing head described below and the battery cell described above can be referred to in correspondence with each other.

[0069] See also Figure 5 In this embodiment, the pressure angle head is used to form a pressure angle structure in the battery cell as described in any of the above embodiments, including: a pressure angle body, a pressure angle R corner portion located at one side edge of the pressure angle body, and a pressure angle protrusion protruding from one side edge of the pressure angle body; the pressure angle protrusion is arranged close to one end of the pressure angle R corner portion, and a preset interval is arranged between the pressure angle protrusion and one end of the pressure angle R corner portion to form a pressure angle avoidance portion.

[0070] The above-mentioned angle-pressing body is the main structure of the angle-pressing head, while the angle-pressing R corner portion, the angle-pressing convex portion and the angle-pressing gap portion are structures arranged on the edge of the angle-pressing body. The angle-pressing structure formed in the battery cell during use is mainly based on the corresponding structure formed by the above-mentioned angle-pressing R corner portion, the angle-pressing convex portion and the angle-pressing gap portion. The specific correspondence between the above-mentioned angle-pressing head and the angle-pressing structure has been described in detail in the above-mentioned embodiments and will not be repeated here. The specific structure of the angle-pressing head corresponds to the specific structure of the angle-pressing structure.

[0071] The angle-pressing head provided in this embodiment is specifically used to form the above-mentioned angle-pressing structure, which can leave a margin for the deformation of the membrane shell 1 during subsequent use, so as to reduce the probability of the bottom corner of the membrane shell 1 being broken.

[0072] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0073] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0074] The above is a detailed introduction to a battery cell and a corner pressing head provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A battery cell, characterized in that: It includes a battery cell body and a shell covering the battery cell body; the shell includes a film shell for accommodating the battery cell body, and the film shell has a bottom corner portion; The housing is provided with a pressure angle structure, the pressure angle structure includes an R corner portion and a convex portion, and a space-avoiding portion is formed between the convex portion and the R corner portion; The R-corner portion is provided along a portion of the edge of the bottom corner portion, and the avoidance portion extends to another portion of the edge of the bottom corner portion.

2. The battery cell according to claim 1, characterized in that The R angle of the R corner portion is greater than the R angle of the bottom corner portion.

3. The battery cell according to claim 1, characterized in that The housing further comprises a sealing area located outside the membrane shell, and an inner unsealed area located between the membrane shell and the sealing area; The air-avoiding portion is arranged in the inner unsealed area.

4. The battery cell according to claim 3, characterized in that The width of the R corner portion ranges from 0.3 mm to 2 mm, the R angle size of the R corner portion ranges from 1.5 mm to 2.5 mm, and the width of the air avoidance portion ranges from 0 mm to 3 mm.

5. The battery cell according to claim 1, characterized in that There is a back margin between the bottom corner portion and the back of the shell, and the back margin is not less than 1.4 mm.

6. The battery cell according to claim 5, characterized in that The back margin has a value range of 1.4 mm to 4.0 mm.

7. The battery cell according to claim 1, characterized in that The battery cell body includes a positive electrode sheet and a negative electrode sheet. The negative electrode sheet includes a negative electrode current collector and a negative electrode paste layer. The negative electrode paste layer is a graphite paste layer, a silicon-based material paste layer, or a mixed paste layer of graphite and silicon-based materials.

8. The battery cell according to claim 7, characterized in that: The absolute strength of the negative electrode current collector ranges from 450 N / m to 1000 N / m.

9. The battery cell according to claim 7, characterized in that: The thickness of the negative electrode current collector ranges from 1 μm to 15 μm.

10. A corner pressure head, characterized in that: For forming the angle-pressing structure in the battery cell according to any one of claims 1 to 9, comprising: A corner pressing body, a corner pressing R corner portion located on one side edge of the corner pressing body, and a corner pressing convex portion protruding from one side edge of the corner pressing body; the corner pressing convex portion is arranged close to one end portion of the corner pressing R corner portion, and a preset interval is arranged between the corner pressing convex portion and one end portion of the corner pressing R corner portion to form a corner pressing avoidance portion.

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