Battery diaphragm, single battery and electric equipment

Abstract

The utility model relates to the technical field of batteries, and discloses a battery diaphragm, a single battery and electric equipment, the battery diaphragm comprises a diaphragm body, the diaphragm body has a length direction and a width direction which are intersected in a plane, and the diaphragm body comprises a first part, a second part and a third part which extend along the length direction; the first part and the third part are oppositely arranged on the two sides of the width direction, and the second part is arranged between the first part and the third part; the porosity of the second part is larger than that of the first part and that of the third part, and the air permeability of the second part is smaller than that of the first part and that of the third part. The porosity and the air permeability are closely related to the wettability of the diaphragm body, so that the wettability of the middle part of the diaphragm body is superior to that of the two side parts, the infiltration process of electrolyte to the middle position is accelerated, and the production efficiency is improved; lithium precipitation at the middle position of the pole piece is avoided, the cycle life of the battery is prolonged, and the safety is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery separator, a single battery and an electrical equipment. Background Art

[0002] At present, as a core component of new energy electric vehicles, batteries have attracted increasing attention in the industry. Among them, large cylindrical batteries are made into compact cores by winding technology, and have advantages such as high energy density, high safety, and high consistency.

[0003] In the preparation process of large cylindrical batteries, the electrolyte needs to gradually penetrate from both ends of the core to the middle position to complete the wetting of the electrode sheets. For the entire separator, the time for the electrolyte to penetrate from both sides of the separator to the middle is relatively long, and the wetting process is slow, resulting in low production efficiency of the battery. Moreover, after the battery is cycled, the electrolyte will be consumed, and large expansion forces will be generated on the electrode sheets, causing stress on the middle position of the core, making it difficult for the electrolyte to effectively penetrate from both ends of the core to the middle position, and easily causing lithium plating at the middle position of the electrode sheets, reducing the cycle life and causing battery safety problems.

[0004] In summary, for the existing large cylindrical batteries, the wetting process of the electrolyte from both sides of the separator to the middle is slow, and the production efficiency is low; moreover, after the battery is cycled, stress is generated in the middle of the core, which easily causes lithium plating at the middle position of the electrode sheets, reducing the battery cycle life and posing safety problems. Content of the Utility Model

[0005] The technical problem to be solved by the utility model is that for the existing large cylindrical batteries, the wetting process of the electrolyte from both sides of the separator to the middle is slow, and the production efficiency is low; and after the battery is cycled, lithium plating easily occurs at the middle position of the electrode sheets, reducing the battery cycle life and posing safety problems.

[0006] To solve the above technical problems, the utility model provides a technical solution for a battery separator:

[0007] The battery separator includes:

[0008] A separator body, the separator body has a length direction and a width direction intersecting in the plane, and the separator body includes a first part, a second part and a third part extending along the length direction;

[0009] The first part and the third part are oppositely arranged on both sides in the width direction, and the second part is arranged between the first part and the third part;

[0010] The porosity of the second part is greater than that of the first part and the third part, and the air permeability of the second part is less than that of the first part and the third part.

[0011] Further, the total width of the diaphragm body is W0, the width of the first part is W1, the width of the second part is W2, and the width of the third part is W3, where W0 ≥ W1 + W2 + W3.

[0012] Further, the total width of the diaphragm body is W0, the width of the first part is W1, the width of the second part is W2, and the width of the third part is W3, where 5% * W0 ≤ W2 ≤ 50% * W0.

[0013] Further, the diaphragm body includes a base film layer. The porosity of the base film layer of the second part is 35% - 60%, and the porosity of the base film layer of the first part and the third part is 20% - 55%.

[0014] Further, the air permeability of the base film layer of the second part is 50 s / 100 cc - 200 s / 100 cc, and the air permeability of the base film layer of the first part and the third part is 80 s / 100 cc - 290 s / 100 cc.

[0015] Further, the diaphragm body further includes a coating provided on the surface of the base film layer. The porosity of the coating of the second part is 40% - 80%, and the porosity of the coating of the first part and the third part is 30% - 70%.

[0016] Further, the air permeability of the coating of the second part is 10 s / 100 cc - 150 s / 100 cc, and the air permeability of the coating of the first part and the third part is 45 s / 100 cc - 185 s / 100 cc.

[0017] Further, the porosity of the first part and the third part gradually increases along the width direction towards the second part, and the porosity of the second part gradually increases from both sides to the middle along the width direction;

[0018] The air permeability of the first part and the third part gradually decreases along the width direction towards the second part, and the air permeability of the second part gradually decreases from both sides to the middle along the width direction.

[0019] To solve the above technical problems, the present utility model provides a technical solution for a single cell having the above battery diaphragm:

[0020] A single cell includes: a battery diaphragm, the battery diaphragm includes a diaphragm body, the diaphragm body has a length direction and a width direction intersecting in the plane, and the diaphragm body includes a first part, a second part, and a third part extending along the length direction;

[0021] The first part and the third part are relatively arranged on both sides in the width direction, and the second part is arranged between the first part and the third part;

[0022] The porosity of the second part is greater than that of the first part and the third part, and the air permeability of the second part is less than that of the first part and the third part.

[0023] Further, the total width of the diaphragm body is W0, the width of the first part is W1, the width of the second part is W2, and the width of the third part is W3, and W0≥W1+W2+W3.

[0024] Further, the total width of the diaphragm body is W0, the width of the first part is W1, the width of the second part is W2, and the width of the third part is W3, and 5%*W0≤W2≤50%*W0.

[0025] Further, the diaphragm body includes a base film layer. The porosity of the base film layer of the second part is 35% to 60%, and the porosity of the base film layer of the first part and the third part is 20% to 55%.

[0026] Further, the air permeability of the base film layer of the second part is 50s / 100cc to 200s / 100cc, and the air permeability of the base film layer of the first part and the third part is 80s / 100cc to 290s / 100cc.

[0027] Further, the diaphragm body further includes a coating provided on the surface of the base film layer. The porosity of the coating of the second part is 40% to 80%, and the porosity of the coating of the first part and the third part is 30% to 70%.

[0028] Further, the air permeability of the coating of the second part is 10s / 100cc to 150s / 100cc, and the air permeability of the coating of the first part and the third part is 45s / 100cc to 185s / 100cc.

[0029] Further, the porosity of the first part and the third part gradually increases along the width direction towards the second part, and the porosity of the second part gradually increases from both sides to the middle along the width direction;

[0030] The air permeability of the first part and the third part gradually decreases along the width direction towards the second part, and the air permeability of the second part gradually decreases from both sides to the middle along the width direction.

[0031] To solve the above technical problems, the present utility model provides a technical solution for an electrical device having the above-mentioned single cell:

[0032] An electrical device, comprising: a single cell, the single cell including a battery separator, the battery separator including a separator body, the separator body having a length direction and a width direction intersecting in the plane, the separator body including a first part, a second part, and a third part extending along the length direction;

[0033] The first part and the third part are oppositely arranged on both sides in the width direction, and the second part is arranged between the first part and the third part;

[0034] The porosity of the second part is greater than the porosity of the first part and the third part, and the air permeability of the second part is less than the air permeability of the first part and the third part.

[0035] Further, the total width of the separator body is W0, the width of the first part is W1, the width of the second part is W2, and the width of the third part is W3, and W0≥W1+W2+W3.

[0036] Further, the total width of the separator body is W0, the width of the first part is W1, the width of the second part is W2, and the width of the third part is W3, and 5%*W0≤W2≤50%*W0.

[0037] Further, the separator body includes a base film layer, the porosity of the base film layer of the second part is 35% to 60%, and the porosity of the base film layer of the first part and the third part is 20% to 55%.

[0038] Further, the air permeability of the base film layer of the second part is 50s / 100cc to 200s / 100cc, and the air permeability of the base film layer of the first part and the third part is 80s / 100cc to 290s / 100cc.

[0039] Further, the separator body further includes a coating provided on the surface of the base film layer, the porosity of the coating of the second part is 40% to 80%, and the porosity of the coating of the first part and the third part is 30% to 70%.

[0040] Further, the air permeability of the coating of the second part is 10 s / 100 cc to 150 s / 100 cc, and the air permeabilities of the coatings of the first part and the third part are both 45 s / 100 cc to 185 s / 100 cc.

[0041] Further, the porosity of the first part and the third part gradually increases towards the second part along the width direction, and the porosity of the second part gradually increases from both sides to the middle along the width direction;

[0042] The air permeabilities of the first part and the third part gradually decrease towards the second part along the width direction, and the air permeability of the second part gradually decreases from both sides to the middle along the width direction.

[0043] Compared with the prior art, a battery separator, a single cell and an electrical device of the present utility model have the beneficial effects that: the battery separator includes a separator body, the separator body includes a first part, a second part and a third part extending along the length direction, and the first part and the third part are on both sides of the separator body in the width direction, and the second part is arranged between the first part and the third part, so that three regions of middle + both sides are formed on the separator body.

[0044] Since the porosity of the second part is greater than that of the first part and the third part, and the air permeability of the second part is less than that of the first part and the third part, and both the porosity and the air permeability are closely related to the wettability of the separator body, the wettability of the second part is better than that of the first part and the third part, that is, the wettability of the middle part of the separator body is better than that of the two side parts, which speeds up the penetration and wetting process of the electrolyte to the middle position, improves the production efficiency; moreover, it avoids the easy lithium deposition at the middle position of the electrode plate after the battery cycle, prolongs the battery cycle life and ensures safety. Description of the Drawings

[0045] Figure 1 is a plan view of the battery separator in the embodiment of the present utility model;

[0046] Figure 2 is a cross-sectional view of the battery separator in the embodiment of the present utility model;

[0047] Figure 3 is an internal view of the single cell with the separator body in the embodiment of the present utility model;

[0048] In the figure: 1 - diaphragm body, 10 - base film layer, 101 - coating, 11 - first part, 12 - second part, 13 - third part, 110 - base film layer of the first part, 120 - base film layer of the second part, 130 - base film layer of the third part, 111 - coating of the first part, 121 - coating of the second part, 131 - coating of the third part, 2 - electrode, X - length direction, Y - width direction, Z - thickness direction. Detailed implementation manners

[0049] The following combines the accompanying drawings and embodiments to further describe in detail the specific implementation manners of the present utility model. The following embodiments are used to illustrate the present utility model, but are not used to limit the scope of the present utility model.

[0050] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. in the present utility model is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model.

[0051] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0052] In the present utility model, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0053] Such as Figure 1 、 Figure 2As shown in the figure, a battery separator according to an embodiment of the present utility model includes: a separator body 1. The separator body 1 has a length direction X and a width direction Y that intersect in the plane. The separator body 1 includes a first portion 11, a second portion 12, and a third portion 13 that extend along the length direction X. The first portion 11 and the third portion 13 are oppositely arranged on both sides of the width direction Y, and the second portion 12 is arranged between the first portion 11 and the third portion 13. The porosity of the second portion 12 is greater than that of the first portion 11 and the third portion 13, and the air permeability of the second portion 12 is less than that of the first portion 11 and the third portion 13.

[0054] This battery separator includes a separator body 1. The separator body 1 includes a first portion 11, a second portion 12, and a third portion 13 that extend along the length direction. Moreover, the first portion 11 and the third portion 13 are on both sides of the width direction Y of the separator body 1, and the second portion 12 is arranged between the first portion 11 and the third portion 13, thereby forming three regions of "middle + two sides" on the separator body 1.

[0055] Since the porosity of the second portion 12 is greater than that of the first portion 11 and the third portion 13, and the air permeability of the second portion 12 is less than that of the first portion 11 and the third portion 13, and both the porosity and the air permeability are closely related to the wettability of the separator body 1, the wettability of the second portion 12 is better than that of the first portion 11 and the third portion 13, that is, the wettability of the middle part of the separator body 1 is better than that of the two side parts, which speeds up the penetration and wetting process of the electrolyte to the middle position, improves the production efficiency; moreover, it avoids the easy lithium deposition at the middle position of the electrode sheet after battery cycling, extends the battery cycle life, and ensures safety.

[0056] In this embodiment, the total width of the separator body 1 is W0, the width of the first portion 11 is W1, the width of the second portion 12 is W2, and the width of the third portion 13 is W3, and W0 = W1 + W2 + W3. Specifically, the total width of the separator body 1 is W0, the width of the first portion 11 is W1, the width of the second portion 12 is W2, and the width of the third portion 13 is W3, 5% * W0 ≤ W2 ≤ 50% * W0, and W1 = W3. The first portion 11, the second portion 12, and the third portion 13 that extend along the length direction X form the entire separator body 1. The width W2 of the second portion 12 = 5% * W0. Correspondingly, W1 = W3 = 47.5% * W0.

[0057] To meet different usage requirements, in other embodiments, the width W2 of the second part = 10% * W0. Correspondingly, W1 = W3 = 45% * W0. Or, the width W2 of the second part = 20% * W0. Correspondingly, W1 = W3 = 40% * W0. Or, the width W2 of the second part = 30% * W0. Correspondingly, W1 = W3 = 35% * W0. Or, the width W2 of the second part = 40% * W0. Correspondingly, W1 = W3 = 30% * W0. Or, the width W2 of the second part = 50% * W0. Correspondingly, W1 = W3 = 25% * W0.

[0058] A preparation method of the battery separator: Pretreat raw materials such as polyethylene and pore-forming agent in a certain proportion and then send them to an extrusion system. Then, after uniform melting and plasticization by the extrusion system, the melt is extruded from a die. After calendaring, a base film layer with a specific crystal structure is formed. Then, the base film layer is longitudinally stretched. The temperature at the middle position in the longitudinal direction is different from that on both sides. In this way, different porosities can be formed in the width direction Y under the condition of the same draw-through speed. Then, after transverse stretching, solvent elution, and drying and shaping, the finished separator is obtained.

[0059] Another preparation method of the battery separator: The separator is composed of two different polyethylene raw materials. The middle is a polyethylene material with a high porosity, and both sides are polyethylene materials with a low porosity. Pretreat the two polyethylenes and raw materials such as pore-forming agent in a certain proportion and then send them to an extrusion system. The extrusion system has different flow channels for distinction. The middle flow channel passes through the polyethylene material system with a high porosity, and the flow channels on both sides pass through the polyethylene material system with a low porosity. Then, after uniform melting and plasticization by the extrusion system, the melt is extruded from a die. After calendaring, a base film layer with a specific crystal structure is formed. Then, the base film layer is longitudinally stretched to form different porosities in the width direction Y. Then, after transverse stretching, solvent elution, and drying and shaping, the finished separator is obtained.

[0060] Among them, the separator body 1 includes a base film layer 10. The porosity of the base film layer 120 of the second part is 35% - 60%. The porosities of the base film layer 110 of the first part and the base film layer 130 of the third part are both 20% - 55%. And, the air permeability of the base film layer 120 of the second part is 50 s / 100 cc - 200 s / 100 cc. The air permeabilities of the base film layer 110 of the first part and the base film layer 130 of the third part are both 80 s / 100 cc - 290 s / 100 cc.

[0061] The separator body 1 further includes a coating 101 provided on the surface of the base film layer 10. The porosity of the second part of the coating 121 is 40% - 80%, and the porosities of the first part of the coating 111 and the third part of the coating 131 are both 30% - 70%. Moreover, the air permeability of the second part of the coating 121 is 10 s / 100cc - 150 s / 100cc, and the air permeabilities of the first part of the coating 111 and the third part of the coating 131 are both 45 s / 100cc - 185 s / 100cc.

[0062] Specifically, the base film layer 10 is a PE film layer with a thickness of 0.009 mm, and the coating 101 is a single-sided ceramic coating with a thickness of 0.003 mm. The second part 12 of the separator body 1 is defined as the middle part, and the first part 11 and the third part 13 of the separator body 1 are defined as the two side parts. In Embodiment 1 of the present utility model, the width W2 of the second part 12 is selected as 5% * W0, and the widths of the first part 11 and the third part 13 are W1 = W3 = 47.5% * W0. The porosity of the middle part is selected as 45%, where the porosity refers to the total porosity of the base film layer 120 and the coating 121 of the second part; the air permeability of the middle part is 140 s / 100cc, where the air permeability refers to the air permeability of the base film layer 120 and the coating 121 of the second part.

[0063] Correspondingly, the porosity of the two side parts is selected as 40%, where the porosity refers to the total porosity of the base film layer 110 and the coating 111 of the first part and the total porosity of the base film layer 130 and the coating 131 of the third part; the air permeability of the two side parts is 170 s / 100cc, where the air permeability refers to the total air permeability of the base film layer 110 and the coating 111 of the first part and the total air permeability of the base film layer 130 and the coating 131 of the third part. The separator body 1 with the above parameters is subjected to an infiltration and cycle life test, and the infiltration time is obtained as 44 h and the cycle life is 600 cycles, both of which are better than the performance of conventional battery separators.

[0064] In addition, in Embodiment 2 of the present utility model, the width W2 of the second part is selected as 10% * W0, the porosity of the middle part is selected as 45%, the air permeability of the middle part is 140 s / 100cc, the porosity of the two side parts is selected as 40%, and the air permeability of the two side parts is 170 s / 100cc. The separator body with the above parameters is subjected to an infiltration and cycle life test, and the infiltration time is obtained as 40 h and the cycle life is 800 cycles, both of which are better than the performance of conventional battery separators.

[0065] In Embodiment 3 of the present utility model, the width W2 of the second part is selected as 20% * W0, the porosity of the middle part is selected as 45%, the air permeability of the middle part is 140 s / 100 cc, the porosity of the two side parts is selected as 40%, and the air permeability of the two side parts is 170 s / 100 cc. The diaphragm body with the above parameters is subjected to infiltration and cycle life tests, and the infiltration time is obtained as 32 h and the cycle life is 1000 cycles, both of which are superior to the performance of conventional battery diaphragms.

[0066] In Embodiment 4 of the present utility model, the width W2 of the second part is selected as 30% * W0, the porosity of the middle part is selected as 45%, the air permeability of the middle part is 140 s / 100 cc, the porosity of the two side parts is selected as 40%, and the air permeability of the two side parts is 170 s / 100 cc. The diaphragm body with the above parameters is subjected to infiltration and cycle life tests, and the infiltration time is obtained as 22 h and the cycle life is 1500 cycles, both of which are superior to the performance of conventional battery diaphragms.

[0067] In Embodiment 5 of the present utility model, the width W2 of the second part is selected as 50% * W0, the porosity of the middle part is selected as 45%, the air permeability of the middle part is 140 s / 100 cc, the porosity of the two side parts is selected as 40%, and the air permeability of the two side parts is 170 s / 100 cc. The diaphragm body with the above parameters is subjected to infiltration and cycle life tests, and the infiltration time is obtained as 12 h and the cycle life is 2000 cycles, both of which are superior to the performance of conventional battery diaphragms.

[0068] In Embodiment 6 of the present utility model, the width W2 of the second part is selected as 30% * W0, the porosity of the middle part is selected as 50%, the air permeability of the middle part is 110 s / 100 cc, the porosity of the two side parts is selected as 40%, and the air permeability of the two side parts is 170 s / 100 cc. The diaphragm body with the above parameters is subjected to infiltration and cycle life tests, and the infiltration time is obtained as 14 h and the cycle life is 1800 cycles. Comparing with Embodiment 4, it can be seen that the infiltration performance is further improved.

[0069] In Embodiment 7 of the present utility model, the width W2 of the second part is selected as 30% * W0, the porosity of the middle part is selected as 45%, the air permeability of the middle part is 140 s / 100 cc, the porosity of the two side parts is selected as 30%, and the air permeability of the two side parts is 230 s / 100 cc. The diaphragm body with the above parameters is subjected to infiltration and cycle life tests, and the infiltration time is obtained as 28 h and the cycle life is 1200 cycles, both of which are superior to the performance of conventional battery diaphragms. As shown in the following table:

[0070]

[0071]

[0072] In addition, in other embodiments, the base film layer can be not only a PE film layer, but also any one of a PP film layer, a PP / PE composite film layer, and a cellulose film layer; correspondingly, the coating can also be any one of a double-sided ceramic coating, a single-sided adhesive layer, and a double-sided adhesive layer.

[0073] To meet different usage requirements, in other embodiments, the porosity of the first part and the third part gradually increases along the width direction Y towards the second part, and the porosity of the second part gradually increases from both sides to the middle along the width direction Y; correspondingly, the air permeability of the first part and the third part gradually decreases along the width direction Y towards the second part, and the air permeability of the second part gradually decreases from both sides to the middle along the width direction Y. That is, the porosity of the first part, the third part, and the second part of the separator body is gradually increased from both sides to the middle, and the porosity of the first part, the third part, and the second part of the separator body is gradually decreased from both sides to the middle, which can also make the wetting performance of the middle part of the separator body better than that of the two side parts.

[0074] A single cell according to an embodiment of the present invention, such as Figure 3 shown, the single cell includes a cell separator 1 and an electrode 2, and the single cell is specifically a cylindrical cell. Figure 3 The cross-sectional structure of the single cell in the width direction Y and the thickness direction Z of the cell separator 1 is shown, wherein the cell separator 1 is the cell separator in the above-mentioned embodiment of the present invention, which will not be elaborated here.

[0075] An electrical device according to an embodiment of the present invention, the electrical device includes a single cell, wherein the single cell is the single cell in the above-mentioned embodiment of the present invention, which will not be elaborated here.

[0076] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and replacements can be made, and these improvements and replacements should also be regarded as the protection scope of the present invention.

Claims

1. A battery separator, characterized in that: include: A diaphragm body (1), the diaphragm body (1) having a length direction (X) and a width direction (Y) intersecting in a plane, the diaphragm body (1) comprising a first portion (11), a second portion (12) and a third portion (13) extending along the length direction (X); The first part (11) and the third part (13) are arranged on both sides of the width direction (Y) relatively to each other, and the second part (12) is arranged between the first part (11) and the third part (13); The porosity of the second part (12) is greater than the porosity of the first part (11) and the third part (13), and the air permeability of the second part (12) is less than the air permeability of the first part (11) and the third part (13).

2. The battery separator according to claim 1, characterized in that: The total width of the diaphragm body (1) is W0, the width of the first part (11) is W1, the width of the second part (12) is W2, the width of the third part (13) is W3, and W0≥W1+W2+W3.

3. The battery separator according to claim 1, characterized in that: The total width of the diaphragm body (1) is W0, the width of the first part (11) is W1, the width of the second part (12) is W2, the width of the third part (13) is W3, and 5%*W0≤W2≤50%*W0.

4. The battery separator according to claim 1, characterized in that: The diaphragm body (1) comprises a base membrane layer (10), the porosity of the base membrane layer (120) of the second part is 35% to 60%, and the porosity of the base membrane layer (110) of the first part and the porosity of the base membrane layer (130) of the third part are both 20% to 55%.

5. The battery separator according to claim 4, characterized in that: The air permeability of the base film layer (120) of the second part is 50s / 100cc to 200s / 100cc, and the air permeability of the base film layer (110) of the first part and the air permeability of the base film layer (130) of the third part are both 80s / 100cc to 290s / 100cc.

6. The battery separator according to claim 4, characterized in that: The diaphragm body (1) further comprises a coating (101) disposed on the surface of the base film layer (10); the porosity of the coating (121) of the second portion is 40% to 80%, and the porosity of the coating (111) of the first portion and the porosity of the coating (131) of the third portion are both 30% to 70%.

7. The battery separator according to claim 6, characterized in that: The air permeability of the coating layer (121) of the second part is 10s / 100cc to 150s / 100cc, and the air permeability of the coating layer (111) of the first part and the air permeability of the coating layer (131) of the third part are both 45s / 100cc to 185s / 100cc.

8. The battery separator according to claim 1, characterized in that: The porosity of the first part (11) and the third part (13) gradually increases along the width direction (Y) toward the second part (12), and the porosity of the second part (12) gradually increases from both sides to the middle along the width direction (Y); The air permeability of the first part (11) and the third part (13) gradually decreases along the width direction (Y) toward the second part (12), and the air permeability of the second part (12) gradually decreases from both sides to the middle along the width direction (Y).

9. A single cell battery, characterized in that: A battery separator is included, wherein the battery separator is the battery separator according to any one of claims 1 to 8.

10. An electrical device, characterized in that: It comprises a single cell, and the single cell is the single cell according to claim 9.

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