Insulating protective film, bare cell, battery and battery pack

Abstract

The present application relates to the technical field of batteries, and provides an insulating protective film, a bare cell, a battery and a battery pack. The insulating protective film provided by the present application can cover the bottom portion, side portions in the length direction, side portions in the width direction and the top portion of an electrode assembly, thereby forming insulating protection for the electrode assembly. In the insulating protective film provided by the embodiments of the present application, the size of a third portion in the width direction is G, and the edge distance of each tab of the electrode assembly is H, and 20％≤G / H≤90％, thus minimizing exposed portions of the electrode assembly outside the tabs as much as possible, improving the insulating performance of the electrode assembly covered by the insulating protective film, preventing electrode sheets outside the tabs from being crushed during assembly, preventing interference between the insulating film and the tabs which affects subsequent ultrasonic welding of the tabs, and avoiding tearing of the tabs.

Description

Insulating protective film, bare battery cell, battery and battery pack

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. CN202411366729.0, filed on September 29, 2024, and entitled “Insulating protective film, bare battery cell, battery and battery pack”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, in particular to an insulating protective film, a bare battery cell, a battery and a battery pack. BACKGROUND

[0004] In the production process of a bare battery cell, an insulating protective film is usually used to coat a pole group, so as to protect the pole group and ensure the insulation performance of the pole group. However, there is still room for improvement in the current technology because there is a lack of unified coating method for the pole group.

[0005] SUMMARY

[0006] Therefore, the present application aims to provide an insulating protective film, a bare battery cell, a battery and a battery pack, which aims to solve the above technical problems to some extent.

[0007] In a first aspect, the present application provides an insulating protective film, which is used to coat a pole group, the pole group has a tab at the top, and the pole group also has a length direction and a width direction, and the insulating protective film comprises:

[0008] a bottom, which is used to coat the bottom of the pole group;

[0009] two first regions, which are respectively located on both sides of the bottom in the width direction;

[0010] wherein the first region comprises a first part and two second parts, the first part is connected to the side of the bottom in the width direction, the two second parts are respectively connected to both sides of the first part in the length direction, and the first region further comprises a third part provided corresponding to each second part, and the third part is connected to the side of the corresponding second part away from the bottom in the width direction;

[0011] the first part is used to coat the side of the pole group in the width direction, the second part is used to coat the side of the pole group in the length direction, and the third part is used to coat the top of the pole group;

[0012] The third portion has a size G in the width direction, and a distance between the tab of the pole group and a side of the pole group in the length direction is a margin H of the tab, 20%≤G / H≤90%.

[0013] Beneficial effects: The insulation protective film can coat the bottom, the length direction side, the width direction side and the top of the pole group, thereby forming insulation protection for the pole group. According to the insulation protective film provided by the embodiment of the application, the size of the third portion in the width direction is G, the margin of the tab of the pole group is H, and 20%≤G / H≤90%. This is beneficial to make the pole group part outside the tab as small as possible, improve the insulation performance of the pole group coated by the insulation protective film, prevent the pole piece outside the tab from being crushed during assembly, avoid the interference between the insulation film and the tab, affect the subsequent ultrasonic welding of the tab, and avoid tearing the tab.

[0014] In an optional embodiment, 60%≤G / H≤80%, the insulation protective film further comprises two second regions, and the two second regions are respectively located on both sides of the bottom in the length direction.

[0015] In an optional embodiment, the first region further comprises a fourth portion connected to a side of the first portion away from the bottom in the width direction,

[0016] The fourth portion has two first inclined sides opposite to each other in the length direction, and an included angle A2 between the first inclined side and a side of the first portion in the width direction satisfies 30°≤A2≤150°.

[0017] And / or, the third portion has a second inclined side close to the first inclined side in the length direction, and an included angle A1 between the second inclined side and a side of the third portion close to the second portion satisfies 30°≤A1≤150°.

[0018] In an optional embodiment, the first region further comprises a fourth portion connected to a side of the first portion away from the bottom in the width direction, and a size E of the fourth portion in the width direction.

[0019] Wherein, the pole group is a wound pole group, a thickness of a single wound pole group is D1, the insulation protective film is used for coating the wound pole group, and 3mm≤E≤(0.5D1-3)mm.

[0020] In an optional embodiment, the second portion has a size F in the length direction, the pole groups are wound pole groups, a thickness of a single wound pole group is D1, and (0.5ND1+3) mm≤F≤ND1 mm, where N is the number of the wound pole groups.

[0021] In an optional embodiment, the first region further comprises a fourth portion connected to a side of the first portion away from the bottom in the width direction, the fourth portion has a size E in the width direction;

[0022] where the pole groups are laminated pole groups, a thickness of a single laminated pole group is B3, the insulating protective film is used to coat a single laminated pole group, 3 mm≤E≤0.4B3 mm, or the insulating protective film is used to coat two laminated pole groups, 3 mm≤E≤0.75B3 mm.

[0023] In an optional embodiment, the second portion has a size F in the length direction, the pole groups are laminated pole groups, a thickness of a single laminated pole group is B3, and (0.5NB3+3) mm≤F≤NB3 mm, where N is the number of the laminated pole groups.

[0024] In a second aspect, the present application provides a bare cell comprising the insulating protective film as described above.

[0025] In a third aspect, the present application provides a battery comprising the bare cell as described above.

[0026] In a fourth aspect, the present application provides a battery pack comprising a plurality of batteries as described above. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative effort.

[0028] FIG. 1 shows a schematic diagram of an insulating film according to an embodiment of the present application;

[0029] FIG. 2 shows another schematic diagram of an insulating film according to an embodiment of the present application;

[0030] FIG. 3 shows a schematic diagram of an example of a plurality of pole groups according to an embodiment of the present application;

[0031] FIG. 4 shows a schematic diagram of an example of a single pole group according to an embodiment of the present application;

[0032] FIG. 5 shows a schematic diagram of another example of a single pole group according to an embodiment of the present application;

[0033] FIG. 6 shows a schematic diagram of another example of a plurality of pole groups according to an embodiment of the present application.

[0034] Reference signs: 100 - insulation protective film; 110 - bottom; 111 - first region; 112 - first part; 113 - second part; 114 - third part; 115 - fourth part; 116 - second region; 120 - score; 200 - pole group; 210 - tab; 300 - length direction; 400 - width direction. DETAILED DESCRIPTION

[0035] Embodiments of the present application are described in detail below with reference to the attached drawings, wherein the same or like reference numerals and / or letters in different drawings indicate the same or like components or elements having the same or similar function. The embodiments described below are examples and are intended to explain the present application, and are not intended to limit the present application.

[0036] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplification, the elements of the particular examples in the following description are described and illustrated in a particular arrangement and order. Of course, these are merely examples and are intended to be illustrative of the application and not to limit the application. Furthermore, the application can be implemented in various examples with different arrangements and order of the elements. Such variations are contemplated and can be part of the present application.

[0037] According to a first aspect of the embodiments of the present application, an insulation protective film 100 is provided, and the structure and working principle of the insulation protective film 100 will be described in detail below with reference to FIGS. 1-6.

[0038] According to the insulation protective film 100 provided by the embodiments of the present application, the insulation protective film 100 is used to coat a pole group 200, the pole group 200 has a tab 210 at the top, the pole group 200 also has a length direction 300 and a width direction 400, and the insulation protective film 100 includes a bottom 110 and two first regions 111. In an embodiment, the bottom 110 is used to coat the bottom 110 of the pole group 200, and the two first regions 111 are respectively located on both sides of the bottom 110 in the width direction 400.

[0039] In an embodiment, the first region 111 includes a first part 112 connected to a side of the bottom 110 in the width direction 400, and two second parts 113 respectively connected to two sides of the first part 112 in the length direction 300, and the first region 111 further includes a third part 114 arranged corresponding to each second part 113, and the third part 114 is connected to a side of the corresponding second part 113 away from the bottom 110 in the width direction 400. In an embodiment, the first part 112 is used to cover a side of the pole group 200 in the width direction 400, the second part 113 is used to cover a side of the pole group 200 in the length direction 300, and the third part 114 is used to cover a top of the pole group 200.

[0040] In an embodiment, a size of the third part 114 in the width direction 400 is G, a distance between the tab 210 of the pole group 200 and a side of the pole group 200 in the length direction 300 is a margin H of the tab 210, and 20%≤G / H≤90%.

[0041] In this way, according to the insulation protection film 100 provided in the embodiments of the present application, the bottom 110, the side in the length direction 300, the side in the width direction 400, and the top of the pole group 200 can be covered, so as to form insulation protection for the pole group 200. According to the insulation protection film 100 provided in the embodiments of the present application, the size of the third part 114 in the width direction 400 is G, the margin of the tab 210 of the pole group 200 is H, and 20%≤G / H≤90%, which is beneficial to make the part of the pole group 200 outside the tab 210 as small as possible, improve the insulation performance of the pole group 200 covered by the insulation protection film 100, prevent the pole piece outside the tab 210 from being pressed during assembly, avoid the interference between the insulation film and the tab 210, affect the ultrasonic welding of the tab 210, and avoid tearing the tab 210.

[0042] Based on the above description, Table 1 below lists 15% and 95% outside the above G / H range as comparative examples, and lists multiple examples within the above G / H range as embodiments, and the application results corresponding to each example are marked in Table 1.

[0043] As shown in FIG. 1, FIG. 1 shows a schematic view of the insulation protection film 100, which essentially shows a plan view of the insulation protection film 100. In embodiments, FIG. 1 can be understood as a view obtained by observing the insulation protection film 100 along the height direction of the pole group 200, in which view, the "unfolded" state of the insulation protection film 100 is observed, i.e. the state before the insulation protection film 100 is wrapped onto the pole group 200, and in the subsequent description of the embodiments of the present application, unless it is explicitly indicated that the insulation protection film 100 is wrapped onto the pole group 200, the rest of the description of the orientation is with reference to the example in FIG. 1.

[0044] With continued reference to FIG. 2, FIG. 2 shows a view of the insulation protection film 100 in the same view as in FIG. 1. In FIG. 2, the labels of the specific regions and parts are not shown in detail, but rather the boundaries between the regions and parts are shown. Specifically, in combination with FIG. 1 and with reference to FIG. 2, the different regions and different parts within the regions can be divided by the score lines 120. For example, the bottom 110 and the first region 111 connected to the two sides of the bottom 110 in the width direction 400 are divided by the score lines 120 along the length direction 300. For different parts in the first region 111, for example, between the first part 112 and the second part 113 and between the second part 113 and the third part 114 can be divided by the score lines 120.

[0045] In embodiments, the "score line 120" is essentially a "crease" between different regions and different parts, and after the insulation protection film 100 is wrapped onto the pole group 200, the positions corresponding to the score lines 120 are the "edges" of the pole group 200, and the "edges" referred to herein are not limited to the edges of a cuboid structure, but should also be broadly understood as the intersections of adjacent sides of the pole group 200.

[0046] In embodiments, the score lines 120 are located between different regions and different parts, and the score lines 120 can have a smaller thickness relative to the regions or parts on both sides of the score lines 120, so as to facilitate the rotation of one region relative to another region, in order to achieve the purpose of wrapping onto the surface of the pole group 200. In embodiments, the score lines 120 can be obtained by scoring the insulation protection film 100, in other words, the score lines 120 can be scored on the insulation protection film 100.

[0047] In other examples, the score lines 120 can also be obtained by repeatedly folding the insulation protection film 100 to generate the score lines at the same positions as in FIG. 1 and FIG. 2, and it can also be understood that by repeatedly folding, the thickness of the positions where the score lines are located is still smaller than the thickness of the regions or parts on both sides of the score lines.

[0048] In an embodiment, as an example, both ends of each of the scores 120 can be flush with the outer edge of the insulating protective film 100, or in other words, both ends of each of the scores 120 can be located at the outer edge of the insulating protective film 100. Still referring to FIG. 2, and in combination with FIG. 1, as an example, the score 120 extending along the length direction 300 divides the first region 111 and the bottom 110, however, both ends of the score 120 in the length direction 300 do not reach the edge of the insulating protective film 100.

[0049] Thus, in an embodiment, the insulating protective film 100 is equivalent to "hiding" the scores 120 in terms of the arrangement of the scores 120, and the advantage of this arrangement is that, due to the small thickness of the location of the scores 120, the hiding of the scores 120 is conducive to avoiding the different regions or different parts of the insulating protective film 100 tearing from the end of the score 120 at the outer edge of the insulating protective film 100 to the inside of the insulating protective film 100 when pulling occurs between different regions or different parts during the coating process, which causes damage to the insulating protective film 100 and results in the failure of the insulating protective film 100 to protect the pole group 200.

[0050] As shown in FIG. 1, in an embodiment, the bottom 110 and the first portion 112 of the first region 111 can each be rectangular. In an embodiment, the first portion 112 of the first region 111 is connected to the long side of the bottom 110, and as an example, the first portion 112 can have the same length as the long side of the bottom 110. Also as an example, the second portion 113, the third portion 114, and the fourth portion 115 and the second region 116 to be described later can each be a trapezoid or substantially a trapezoid.

[0051] As an example, the second portion 113 and the third portion 114 can each be, for example, a substantially right-angled trapezoid. One of the bottom sides of the second portion 113 is connected to the wide side of the first portion 112, and the right-angled side of the second portion 113 can be connected to one of the bottom sides of the third portion 114. Here, the "substantially right-angled trapezoid" should be understood as the second portion 113 and the third portion 114 substantially presenting a right-angled trapezoid shape, because in actual applications, the corners of the second portion 113 and the third portion 114 can be formed, for example, into a rounded shape, so that the second portion 113 and the third portion 114 are not strictly "right-angled trapezoids".

[0052] In an embodiment, according to the above description, in combination with FIG. 1, the dimension of the third portion 114 in the width direction 400 is substantially the height of the third portion 114 as a substantially right-angled trapezoid shape, which is specifically shown in FIG. 1.

[0053] In embodiments, since the third portion 114 is wrapped from one side of the top of the jelly-roll 200 in the width direction 400 to the top of the jelly-roll 200, that is, the third portion 114 is away from the edge of the second portion 113, that is, the narrower bottom edge finally faces the tab 210 (see FIGS. 3-6).

[0054] In embodiments, substantially G / H is the percentage of the height of the third portion 114 to the edge distance of the tab 210, if less than 20%, the insulation protection film 100 is insufficiently wrapped on the jelly-roll 200, the so-called "outer side" of the tab 210 is the side of the tab 210 facing away from the other tab 210 in the length direction 300, due to the insufficient wrapping, the jelly-roll 200 tab on this side is excessively exposed, which causes the insulation protection of the tab to be insufficient, and may cause the tab to be crushed in the subsequent process. If greater than 90%, it may cause interference with the tab 210 due to excessive wrapping.

[0055] In addition, as an example, in embodiments, the insulation protection film 100 may, for example, be a Mylar film, after being wrapped on the jelly-roll 200, the insulation protection film 100 can be pasted to the outer side of the jelly-roll 200 by adhesive tape. In addition, in embodiments, although its interpretation has been widely known, it still needs to be explained that the jelly-roll 200 should be understood as including a component formed by the jelly-roll and the separator, and the tab 210 extends outwardly from the jelly-roll. Therefore, it can be understood that after the insulation protection film 100 is wrapped on the outer side of the jelly-roll 200, the two substantially form a bare cell together.

[0056] According to the insulation protection film 100 provided by the embodiments of the present application, further, the value range of G / H may, for example, be preferably 60%≤G / H≤80%, in the preferred range, the amount of the insulation protection film 100 is taken into account, that is, in the case of setting a suitable size of the third portion 114, the area of the third portion 114 is not excessively increased, and the over-wrapping and under-wrapping conditions can be avoided. As an example, G / H may, for example, be any integer value before the percentage sign between 60% and 80%.

[0057] In addition, the insulation protection film 100 can further include two second regions 116, the two second regions 116 are respectively located on both sides of the bottom 110 in the length direction 300, as an example, the two second regions 116 and the fourth portion 115 to be described later may, for example, be formed in a substantially isosceles trapezoidal shape (still not a strictly isosceles trapezoidal shape due to the setting of the rounded corners), and the bottom edge of the second region 116 can be connected with the wide edge of the bottom 110.

[0058] According to the insulating protective film 100 provided by the embodiment of the present application, the first area 111 can further include a fourth part 115, the fourth part 115 can be connected to the side of the first part 112 away from the bottom 110 in the width direction 400, the fourth part 115 has two first inclined side parts (i.e. the two legs of the isosceles trapezoid mentioned above) opposite to each other in the length direction 300, and the included angle A2 between the first inclined side part and the side of the first part 112 in the width direction 400 can satisfy 30°≤A2≤150°. Alternatively or simultaneously, the third part 114 can have a second inclined side part (i.e. the inclined leg of the right-angled trapezoid above) close to the first inclined side part in the length direction 300, and the included angle A1 between the second inclined side part and the side of the third part 114 close to the second part 113 satisfies 30°≤A1≤150°. That is, 30°≤A2≤150° and / or 30°≤A1≤150°.

[0059] In the embodiment, the above-mentioned included angles A1 and A2 take the above-mentioned angle range, which can ensure that both the third part 114 and the fourth part 115 form an overlapping area after being wrapped together to the top of the pole group 200, thereby effectively protecting the pole group 200, and in particular, effectively protecting the pole pieces in the pole group 200. In the embodiment, the preferred angle range of A1 and A2 can be, for example, 80°≤A1≤120°, and in particular, any integer angle value in the range.

[0060] According to the insulating protective film 100 provided by the embodiment of the present application, the size of the fourth part 115 in the width direction 400 is E, that is, the height of the fourth part 115 as a substantially isosceles trapezoid is E. In the embodiment, the pole group 200 can be, for example, a wound pole group, the thickness of a single wound pole group is D1, and the insulating protective film 100 is used to wrap the wound pole group (for example, the single pole group 200 represented by the two wound pole groups shown in FIG. 3, and the single pole group 200 shown in FIG. 4), and 3mm≤E≤(0.5D1-3)mm.

[0061] In the embodiment, as shown in FIG. 4, FIG. 4 shows a schematic diagram of a three-dimensional view of a single wound pole group. In combination with FIG. 1, in the embodiment, the value of D1 can be, for example, 10mm to 100mm. In the embodiment, the purpose of E being greater than or equal to 3mm is that 3mm is the minimum size of the fourth part 115 that can wrap the top of the pole group 200, and is also the minimum size of the heat melting of the insulating protective film 100 and other components in the subsequent process. The upper limit value of E is (0.5D1-3)mm, which is to avoid the insulating protective film 100 pressing on the pole lug 210 to cause the pole lug 210 to be inserted into the pole group 200 in reverse, thereby causing a short circuit.

[0062] According to the insulating protective film 100 provided in the embodiments of the present application, the size of the second part 113 in the length direction 300 is F, and (0.5ND1+3) mm≤F≤ND1 mm, where N is the number of the wound pole groups.

[0063] In this way, according to the insulating protective film 100 provided in the embodiments of the present application, after the insulating protective film 100 is wrapped around the pole group 200, the two second parts 113 are located at the two sides of the pole group 200 in the length direction 300, and the two second parts 113 opposite to each other in the width direction 400 have a width exceeding half of the width of all the wound pole groups, so that the two second parts 113 opposite to each other can form an overlapping protection area after being folded, thereby better improving the insulation performance of the pole group 200. Here, the lower limit value of F exceeding half of the number of the wound pole groups by 3 mm is the minimum value for forming an effective overlapping protection area, and the upper limit of F can obviously be the same as the width of all the wound pole groups.

[0064] According to the above description, different examples of the thickness D1 of the wound pole group, the size F of the second part 113 in the length direction 300, and the number of the pole groups 200 will be specifically given in Table 2 below.

[0065] According to the insulating protective film 100 provided in the embodiments of the present application, the pole group 200 can also be a laminated pole group (for example, the laminated pole group shown in FIGS. 5 and 6), and the thickness of a single laminated pole group is B3, the insulating protective film 100 is used to wrap a single laminated pole group, and 3 mm≤E≤0.4B3 mm.

[0066] In the embodiments, since the pole lug 210 of the laminated pole group is twice as many as that of the wound pole group, the size of the pole lug 210 of the wound pole group is actually larger than that of the wound pole group, so that the upper limit of E is 0.4B3, and here the value range of B3 can also be, for example, 10 mm to 100 mm.

[0067] According to the insulating protective film 100 provided in the embodiments of the present application, the insulating protective film 100 can also be used to wrap two laminated pole groups, and 3 mm≤E≤0.75B3 mm.

[0068] Further, for the laminated pole group, F can satisfy (0.5NB3+3) mm≤F≤NB3 mm, where N is the number of the laminated pole groups, and here the purpose of the value of F is the same as described above, and will not be described here again.

[0069] According to the above description, different examples of the thickness B3 of the laminated pole group, the size F of the second part 113 in the length direction 300, and the number of the pole groups 200 will be specifically given in Table 3 below.

[0070] According to a second aspect of the embodiments of the present application, a bare cell is provided, the bare cell comprising the insulating protective film 100 as above, and further comprising the pole group 200 as above, the pole group 200 being wrapped by the insulating protective film 100 to form the bare cell.

[0071] According to a third aspect of the embodiments of the present application, a battery is provided, the battery comprising the bare cell as above, and further comprising a shell, the bare cell being arranged inside the shell to form the battery.

[0072] According to a fourth aspect of the embodiments of the present application, a battery pack is provided, the battery pack comprising a plurality of batteries as above, and further comprising a box, the plurality of batteries as above being arranged in the box to form a battery module.

[0073] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and the scope of the present application, and the scope of the present application is defined by the claims and their equivalents. Industrial applicability

[0074] The insulating protective film of the present application can wrap the bottom, the length-direction side, the width-direction side and the top of the pole group to form insulation protection for the pole group. According to the insulating protective film provided by the embodiments of the present application, the third part has a width-direction size G, the pole lug of the pole group has a margin H, and 20%≤G / H≤90%. This is advantageous for making the pole group part outside the pole lug as small as possible, improving the insulation performance of the pole group wrapped by the insulating protective film, preventing the pole piece outside the pole lug from being crushed during assembly, avoiding the interference between the insulating film and the pole lug, affecting the subsequent ultrasonic welding of the pole lug, and avoiding the tearing of the pole lug.

Claims

1. An insulating protective film, characterized by, The insulating protective film is used for cladding a pole group, the pole group has a pole lug at the top, the pole group also has a length direction and a width direction, and the insulating protective film comprises: a bottom, which is used for cladding the bottom of the pole group; two first regions, which are respectively located on both sides of the bottom in the width direction; wherein the first region comprises a first part and two second parts, the first part is connected to the side of the bottom in the width direction, the two second parts are respectively connected to both sides of the first part in the length direction, and the first region further comprises a third part arranged corresponding to each second part, and the third part is connected to the side of the corresponding second part away from the bottom in the width direction; the first part is used for cladding the side of the pole group in the width direction, the second part is used for cladding the side of the pole group in the length direction, and the third part is used for cladding the top of the pole group; the size of the third part in the width direction is G, the distance between the pole lug of the pole group and the side of the pole group in the length direction is the margin H of the pole lug, and 20%≤G / H≤90%.

2. The insulating protective film according to claim 1, characterized by 60%≤G / H≤80%, and the insulating protective film further comprises two second regions, which are respectively located on both sides of the bottom in the length direction.

3. The insulating protective film according to claim 1, wherein the first region further comprises a fourth part connected to the side of the first part away from the bottom in the width direction, the fourth part has two first inclined side parts opposite to each other in the length direction, and the included angle A2 between the first inclined side part and the side part of the first part in the width direction satisfies 30°≤A2≤150°; and / or, the third part has a second inclined side part close to the first inclined side part in the length direction, and the included angle A1 between the second inclined side part and the side part of the third part close to the second part satisfies 30°≤A1≤150°.

4. The insulating protective film according to claim 1, characterized by the first region further comprises a fourth part connected to the side of the first part away from the bottom in the width direction, and the size of the fourth part in the width direction is E; wherein the pole group is a wound pole group, the thickness of a single wound pole group is D1, the insulating protective film is used for cladding the wound pole group, and 3mm≤E≤(0.5D1-3)mm.

5. The insulating protective film according to any one of claims 1 to 4, characterized by, the size of the second part in the length direction is F, the pole group is a wound pole group, the thickness of a single wound pole group is D1, and (0.5ND1+3)mm≤F≤ND1 mm, wherein N is the number of the wound pole groups.

6. The insulating protective film according to claim 1, characterized by the first region further comprises a fourth part connected to the side of the first part away from the bottom in the width direction, and the size of the fourth part in the width direction is E; The pole group is a laminated pole group, and the thickness of a single laminated pole group is B3. The insulating protective film is used to coat a single laminated pole group, 3mm≤E≤0.4B3 mm, or the insulating protective film is used to coat two laminated pole groups, 3mm≤E≤0.75B3 mm.

7. The insulating protective film according to any one of claims 1, 2, 3, and 6, characterized by, The size of the second part in the length direction is F, the pole group is a laminated pole group, the thickness of a single laminated pole group is B3, and (0.5NB3+3) mm≤F≤NB3 mm, where N is the number of laminated pole groups.

8. A bare cell characterized by, The bare electric core comprises the insulating protective film according to any one of claims 1 to 7.

9. A battery, characterized by The battery comprises the bare electric core according to claim 8.

10. A battery pack, characterized by, The battery pack comprises a plurality of batteries according to claim 9.

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