Battery and battery pack
The application of an insulation layer on the electrode terminal addresses insulation failure risks, ensuring stable insulation and electrical conductivity in battery terminals.
Patent Information
- Application Number
- CN202422224259.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-09-10
AI Technical Summary
During long-term use of the battery, the tape between the electrode ear and the shell is shed due to vibration and electrolyte soaking, which poses a risk of insulation failure and leads to a potential short circuit.
The insulating layer is coated on the surface of the pole ear facing the shell to ensure that the length of the insulating layer meets the specific formula range, avoiding direct contact between the pole ear and the shell, and using a ceramic layer as the insulating material to simplify the production process and reduce costs.
It improves the insulation stability between the electrode and the housing, avoids the risk of short circuit, simplifies production, reduces costs, and ensures the overcurrent capability and performance of the battery.
Smart Images
Figure CN223109174U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of batteries, in particular to batteries and battery packs. Background Art
[0002] A battery generally includes an internal structure and an external structure. The internal structure mainly includes a pole group, and the external structure mainly includes a cover plate and a housing. The housing provides an accommodation space for the pole group. The cover plate and the housing are cooperatively welded to fix the pole group in the internal space, and the pole tabs on the pole group are welded to the pole posts on the cover plate. In the traditional battery structure, an insulating film is wrapped outside the pole group to insulate the pole group from the housing. Generally, a tape sticking method is adopted at the pole tabs of the pole group to achieve insulation protection from the inner wall of the housing.
[0003] However, during the long-term use of the battery, due to mechanical impacts such as vibration of the battery and long-term immersion in the electrolyte, the glue on the tape will fail, and there is a risk that the tape will fall off from the pole tab, resulting in insulation failure between the pole tab and the housing. The overlap between the pole tab and the housing causes the battery to short-circuit and get out of control, posing a huge potential safety hazard. Summary of the Utility Model
[0004] In view of this, the utility model provides a battery and a battery pack to solve the problem of the risk of insulation failure between the pole tab and the housing.
[0005] In a first aspect, the utility model provides a battery, including: a housing having an open end; a cover plate disposed at the open end of the housing to close the housing, and a pole post is disposed on the cover plate; a pole group located inside the housing, the pole group includes a connected pole group body and a pole tab, the pole tab has a free state extending along the Y direction and an assembled state bent along the X direction. When the pole tab is in the free state, the length of the pole tab along the Y direction is L; when the pole tab is in the assembled state, a welding mark is formed on the pole tab to electrically connect the pole tab to the pole post, the size of the welding mark along the X direction is W, and in the X direction, the distance between one end of the welding mark close to the housing and the inner wall of the housing is C; an insulating layer coated on the surface of the pole tab facing the housing. When the pole tab is in the free state, the length a of the insulating layer along the Y direction satisfies the formula: L - W - C + 1 mm ≤ a ≤ L - W.
[0006] Beneficial effects: By adding an insulating layer to the surface of the tab facing the housing side, direct contact between the tab and the housing is avoided, providing insulation protection between the tab and the housing, preventing the battery from short-circuiting. Compared with the traditional method of using adhesive tape on the tab for insulation protection, the insulating layer is directly coated on the surface of the tab, with good stability, not easily falling off, simple production, and lower cost. Also, the step of pasting the tape is eliminated, simplifying the production process and reducing the occupation of the internal space of the battery core. At the same time, by setting the coating length a of the insulating layer on the tab to satisfy the formula L - W - C + mm ≤ a ≤ L - W, the coating length of the insulating layer is related to the length L of the tab itself, the width dimension W of the welding mark, and the distance C between the welding mark and the inner wall of the housing, reasonably setting the length dimension of the insulating layer, which can not only avoid the poor insulation protection due to too short a length of the insulating layer but also avoid affecting the overcurrent capacity of the battery due to too long a length of the insulating layer, thus ensuring the insulation protection of the tab and the housing while guaranteeing the overcurrent capacity of the battery.
[0007] In an optional embodiment, the value range of the dimension W of the welding mark along the X direction is: 1mm ≤ W ≤ 6mm.
[0008] Beneficial effects: It can not only ensure the conductivity between the electrode group and the electrode post, guarantee the battery performance, but also avoid wasting costs.
[0009] In an optional embodiment, the thickness of the electrode group body is T, and the relationship between the length L of the tab along the Y direction and the thickness T of the electrode group body satisfies: T ≤ L ≤ 2T.
[0010] Beneficial effects: Ensure that there is an appropriate ratio between the length of the tab and the thickness of the electrode group. It can not only avoid poor welding with the connecting piece due to too short a tab, guarantee the good conductivity of the battery, but also avoid the increase in weight and waste of cost due to too long a tab.
[0011] In an optional embodiment, the value range of the distance C between the end of the welding mark close to the housing and the inner wall of the housing is: 3mm ≤ C ≤ T / 2.
[0012] Beneficial effects: It is not only convenient for processing and assembly, avoiding short-circuit between the connecting piece and the housing, but also can ensure that the welding mark completely presses on the tabs of each electrode plate, guaranteeing the exertion of the battery energy and thus ensuring the battery performance.
[0013] In an optional embodiment, when the tab is in the free state, the value range of the length a of the insulating layer along the Y direction is: 3mm ≤ a ≤ 60mm.
[0014] Beneficial effects: It can avoid the situation that the insulation layer is too short to provide good insulation protection, and can also avoid the situation that the insulation layer is too long to affect the overcurrent capacity of the battery. That is, while ensuring the insulation protection of the insulation layer between the tab and the housing, the overcurrent capacity of the battery is ensured.
[0015] In an alternative embodiment, when the tab is in the free state, the value range of the dimension b of the insulation layer in the X direction is: 0.05 mm ≤ b ≤ 0.5 mm.
[0016] Beneficial effects: By setting the dimension b of the insulation layer in the X direction to be within the range of 0.05 mm to 0.5 mm, it is ensured that the insulation layer has an appropriate thickness, thereby ensuring that the insulation layer has a good insulation effect.
[0017] In an alternative embodiment, the insulation layer is a ceramic layer.
[0018] Beneficial effects: The ceramic layer has good insulation effect, high stability, mature technology and high reliability.
[0019] In an alternative embodiment, when the tab is in the free state, one side of the insulation layer is flush with the side of the tab close to the electrode group body and extends in the direction away from the electrode group body.
[0020] Beneficial effects: By setting one side of the insulation layer to be flush with the side of the tab close to the electrode group body, that is, the insulation layer extends from the root of the tab, it is beneficial to ensure that the insulation layer covers the position where the tab may come into contact with the housing, thereby ensuring the insulation protection of the tab by the insulation layer.
[0021] In an alternative embodiment, the insulation layer is sprayed on the tab.
[0022] Beneficial effects: The insulation layer is processed by spraying, with high production efficiency, strong covering ability and good surface flatness, which is beneficial to improving the insulation performance.
[0023] In the second aspect, the present invention also provides a battery pack, including: the above-mentioned battery. Since the battery pack includes the battery and has the same effects as the battery, they will not be elaborated here. Description of the Drawings
[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0025] Figure 1 Schematic diagram of the decomposition of a battery according to an embodiment of the present utility model;
[0026] Figure 2 is Figure 1 The front view of the assembled battery shown in the figure;
[0027] Figure 3 is Figure 2 The cross-sectional view in the A-A direction in
[0028] Figure 4 is Figure 3 The partial enlarged schematic diagram of B in
[0029] Figure 5 Schematic diagram of the structure of a pole group with the tab in a free state according to an embodiment of the present utility model;
[0030] Figure 6 Schematic cross-sectional structure diagram of the pole piece tab coated with an insulating layer according to an embodiment of the present utility model.
[0031] Explanation of reference numerals:
[0032] 1. Housing; 2. Cover plate; 201. Pole post; 202. Explosion-proof valve; 203. Liquid injection hole; 204. Rubber plug; 205. Aluminum cover; 3. Pole group; 310. Pole group body; 320. Tab; 330. Welding mark; 340. Insulating layer; 4. Connecting piece. Specific embodiments
[0033] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.
[0034] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 6 , describing the embodiments of the present utility model.
[0035] According to an embodiment of the present utility model, on the one hand, a battery is provided, including: a housing 1, a cover plate 2, a pole group 3 and an insulating layer 340. The housing 1 has an open end; the cover plate 2 is disposed at the open end of the housing 1 to close the housing 1, and a pole post 201 is provided on the cover plate 2; the pole group 3 is located inside the housing 1, and the pole group 3 includes a connected pole group body 310 and a pole tab 320. The pole tab 320 has a free state extending in the Y direction and an assembled state bent in the X direction. When the pole tab 320 is in the free state, the length of the pole tab 320 in the Y direction is L; when the pole tab 320 is in the assembled state, a welding mark 330 is formed on the pole tab 320 to electrically connect the pole tab 320 to the pole post 201. The dimension of the welding mark 330 in the X direction is W, and in the X direction, the distance between the end of the welding mark 330 close to the inner wall of the housing 1 and the inner wall of the housing 1 is C; the insulating layer 340 is coated on the surface of the pole tab 320 facing the housing 1. When the pole tab 320 is in the free state, the length a of the insulating layer 340 in the Y direction satisfies the formula: L - W - C + 1mm ≤ a ≤ L - W. Wherein, the X direction and the Y direction are the directions of the X axis and the Y axis in the XY plane of the rectangular coordinate system, and the XY plane refers to the Figure 1 , Figures 4 to 6 XOY plane shown in
[0036] By applying the battery of this embodiment, by adding the insulating layer 340 on the surface of the pole tab 320 facing the housing 1, it is avoided that the pole tab 320 directly contacts the housing 1, playing an insulating protection role between the pole tab 320 and the housing 1, and avoiding the battery from short-circuiting. Compared with the traditional method of using adhesive tape on the pole tab 320 for insulation protection, the insulating layer 340 is directly coated on the surface of the pole tab 320, with good stability, not easy to fall off, simple production, low cost, and the step of pasting the tape is omitted, simplifying the production process and reducing the occupation of the internal space of the battery core. At the same time, by setting the coating length a of the insulating layer 340 on the pole tab 320 to satisfy the formula L - W - C + 1mm ≤ a ≤ L - W, the coating length of the insulating layer 340 is related to the length L of the pole tab 320 itself, the width dimension W of the welding mark 330, and the distance C between the welding mark 330 and the inner wall of the housing 1, reasonably setting the length dimension of the insulating layer 340, which can not only avoid the poor insulation protection effect due to the too short length of the insulating layer 340, but also avoid affecting the over-current capacity of the battery due to the too long length of the insulating layer 340, so as to ensure the insulating protection effect of the insulating layer 340 between the pole tab 320 and the housing 1 while ensuring the over-current capacity of the battery.
[0037] It should be noted that the electrode group 3 is formed by stacking positive electrode sheets and negative electrode sheets, and adjacent positive electrode sheets and negative electrode sheets are separated by a diaphragm. Each electrode sheet includes a electrode body and an electrode ear. The electrode ear extends from at least part of the foil in the electrode body. The plane where the large surface of the electrode body is located is the YZ plane in the rectangular coordinate system, and the XY plane is perpendicular to the large surface of the electrode body. The direction in which the electrode ear is away from the electrode body is the extension direction of the electrode ear; the electrode ear 320 is in a free state means that the electrode group 3 after lamination is as follows Figure 5 In the form shown, each pole piece and pole ear are in a dispersed state, and the pole ear 320 in a free state extends along the Y direction, and the X direction is the thickness direction of the pole piece; before the pole group 3 is installed in the shell 1, the pole piece and pole ears need to be integrated together by laser welding or the like to form an integrated pole ear 320; the pole ear 320 is in an assembled state, which means that after the pole piece and pole ears are integrated together and bent, the pole ear 320 turns along the X direction, that is, Figures 3 to 4 In the state shown, the pole lug 320 is bent and welded to the connecting piece 4 to form a weld mark 330 on the pole lug 320, and the connecting piece 4 is then welded to the pole 201, thereby realizing the electrical connection between the pole lug 320 and the pole 201. As an alternative embodiment, the pole lug 320 can also be bent and directly welded to the pole 201 to form the weld mark 330.
[0038] In addition, the insulating layer 340 is coated on the surface of the pole ear 320 facing the shell 1. Specifically, when the pole group is formed by lamination, the pole piece coated with the insulating layer 340 is placed in the outermost layer with the insulating layer 340 facing outward. Then, when the pole group is installed in the shell, the side with the insulating layer 340 faces the inner wall of the shell 1. After the pole ear 320 is bent, the insulating layer 340 is located on the surface of the pole ear 320 facing the shell 1, which plays an insulating and protective role for the pole ear 320. It should be noted that the insulating layer 340 is located on the outermost side and will not affect the electrical contact between the adjacent pole pieces and pole ears. The insulating layer 340 avoids the position of the weld mark 330 that needs to be welded, and will not affect the electrical connection between the pole ear 320 and the connecting piece 4. Specifically, in the lamination process, the outermost pole piece is selected to be the pole piece with the insulating layer 340 coated on one side of the pole piece and the pole ear, and the remaining pole pieces are all pole pieces that are not coated with the insulating layer 340.
[0039] Further integration Figure 4 As shown, the limit position of the weld mark 330 is the upper edge of the tab 320. Figure 4In the X direction away from the edge of the housing 1. At this time, the remaining dimension of the tab ear on the tab closest to the housing 1 after removing the welding mark 330 is L - W. Therefore, the maximum value of the length a of the insulating layer 340 along the extending direction of the tab ear is L - W. If a is greater than L - W, the insulating layer 340 will cover the area of the welding mark 330, affecting the welding of the tab ear 320 and the connecting piece 4, affecting the conductivity, and thus the overcurrent capacity. If a is less than L - W - C + 1 mm, the length of the insulating layer 340 is too short, there is a risk of direct contact between the tab ear 320 and the housing 1, and it cannot provide complete insulation protection.
[0040] In one embodiment, the insulating layer 340 is a ceramic layer. The ceramic layer has good insulation effect, high stability, mature technology, and high reliability.
[0041] In one embodiment, the value range of the dimension W of the welding mark 330 in the X direction is: 1 mm ≤ W ≤ 6 mm. A connecting piece 4 is provided between the cover plate and the electrode assembly 3. The connecting piece 4 is welded to the tab ear 320 and the terminal post 201 respectively to realize the electrical connection between the electrode assembly 3 and the terminal post 201. Among them, after the connecting piece 4 is welded to the tab ear 320, a welding mark 330 is formed on the tab ear 320. The dimension of the welding mark 330 in the X direction is the welding mark width. If the dimension W of the welding mark 330 in the X direction is less than 1 mm, the welding mark width is too small, the welding strength is insufficient, and it is easy to fall off, resulting in poor connection between the electrode assembly 3 and the connecting piece 4, affecting the conductivity between the electrode assembly 3 and the terminal post 201, and even causing a short circuit. If the dimension W of the welding mark 330 in the X direction is greater than 6 mm, the welding mark width is too large, the welding is excessive, resulting in unnecessary cost waste. Therefore, by setting the welding mark width to take values between 1 mm and 6 mm, it can not only ensure the conductivity between the electrode assembly 3 and the terminal post 201, ensure the battery performance, but also avoid wasting costs.
[0042] In one embodiment, the thickness of the electrode assembly body 310 is T, and the length L of the tab ear 320 in the Y direction and the thickness T of the electrode assembly body 310 satisfy: T ≤ L ≤ 2T. Further combined with Figure 5 As shown, the thickness refers to the dimension in the "thickness direction" indicated by the arrow in Figure 5 i.e., the dimension along the X-axis. A plurality of electrode plates are stacked in sequence in the thickness direction to form the electrode assembly 3. The extending direction of the tab ear 320 in the free state is the extending direction of the tab ear of the electrode plate, and this direction is the Y direction, perpendicular to the thickness direction. Further combined with Figure 4It can be seen that after the tab 320 is bent, it is welded with the connecting piece 4. If the length L of the tab 320 is less than the thickness T of the electrode group body 310, the length of the tab 320 is too small, and the area of the part that can be used for welding with the connecting piece 4 after bending is too small, which affects welding and may cause poor welding. If the length L of the tab 320 is greater than 2T, the length of the tab 320 is too large, which wastes materials and increases costs and weight. Therefore, by setting the length L of the tab 320 along the Y direction and the thickness T of the electrode group body 310 to satisfy the relationship of T≤L≤2T, it is ensured that the length of the tab 320 and the thickness of the electrode group have a suitable ratio, which can avoid poor welding with the connecting piece 4 due to the tab 320 being too short, ensure that the battery has good conductivity, and avoid the increase in weight and waste of costs due to the tab 320 being too long.
[0043] In one embodiment, the distance C between the end of the weld mark 330 close to the shell 1 and the inner wall of the shell 1 is in the range of 3mm≤C≤T / 2. The distance C between the end of the weld mark 330 close to the shell 1 and the inner wall of the shell 1 refers to the distance between the end of the weld mark 330 close to the shell 1 and the inner wall of the shell 1 when the electrode group is assembled into the shell 1 and the electrode ear 320 is in a bent assembly state. Figure 4 The distance in the "thickness direction" indicated by the middle arrow (i.e., the distance along the X-axis) is also the shortest distance between the weld mark 330 and the inner wall of the shell 1 along the X-direction. If the distance between the end of the weld mark 330 close to the shell 1 and the inner wall of the shell 1 is less than 3 mm, the weld mark is too close to the inner wall of the shell 1, which in turn causes the connecting piece 4 to be too close to the shell 1, which is inconvenient for processing and assembly, and may also cause a short circuit between the connecting piece 4 and the shell 1, affecting the performance of the battery. If the distance between the end of the weld mark 330 close to the shell 1 and the inner wall of the shell 1 is greater than T / 2, the weld mark is too far from the inner wall of the shell 1, and the weld mark 330 is too close to the end of the pole ear 320. Since the ends of the pole pieces and pole ears after bending are uneven, it is difficult to ensure that the weld mark 330 can be completely pressed on all the pole pieces and pole ears. There may be a situation where some pole pieces cannot be electrically connected to other pole pieces through the pole pieces and pole ears, which seriously affects the energy of the battery. Therefore, by setting the distance C between the end of the weld mark 330 close to the shell 1 and the inner wall of the shell 1 to be in the range of 3mm to T / 2, it is convenient to realize processing and assembly and avoid short circuit between the connecting piece 4 and the shell 1, and it can ensure that the weld mark 330 is completely pressed on each pole piece and ear, thereby ensuring the energy of the battery and thus ensuring the battery performance.
[0044] In one embodiment, when the tab 320 is in a free state, the value range of the length a of the insulating layer 340 in the Y direction is: 3 mm ≤ a ≤ 60 mm. This can not only avoid the poor insulation protection due to the too short length of the insulating layer 340, but also avoid the influence on the over-current capacity of the battery due to the too long length of the insulating layer 340, thus ensuring the insulation protection of the insulating layer 340 for the tab 320 and the housing 1 while ensuring the over-current capacity of the battery.
[0045] Preferably, when the tab 320 is in the free state, the value range of the length a of the insulating layer 340 in the Y direction is 10 mm ≤ a ≤ 40 mm.
[0046] In one embodiment, when the tab 320 is in a free state, the value range of the dimension b of the insulating layer 340 in the X direction is: 0.05 mm ≤ b ≤ 0.5 mm. The insulating layer 340 is coated on the surface of the tab 320, and the dimension b of the insulating layer 340 in the X direction is the thickness of the insulating layer 340. If the thickness of the insulating layer 340 is less than 0.05 mm, the insulating layer 340 is too thin and the insulation effect is poor. If the thickness of the insulating layer 340 is greater than 0.5 mm, the insulating layer 340 is too thick, and after the tab of the electrode plate is bent, the insulating layer 340 is prone to cracking and powder falling, affecting its insulation protection performance. Therefore, by setting the dimension b of the insulating layer 340 in the X direction to be within the range of 0.05 mm to 0.5 mm, it is ensured that the insulating layer 340 has a suitable thickness, thereby ensuring that the insulating layer 340 has a good insulation effect.
[0047] Preferably, the value range of the thickness b of the insulating layer 340 is 0.1 mm ≤ b ≤ 0.4 mm.
[0048] In one embodiment, one side of the insulating layer 340 is flush with the side of the tab 320 close to the electrode group body 310 and extends in the direction away from the electrode group body 310. Further combined with Figure 4 It can be seen that the position where the tab 320 contacts the housing 1 is relatively close to the root position where the tab 320 is connected to the electrode group body 310. The insulating layer 340 is coated on the surface of the tab 320. By setting one side of the insulating layer 340 to be flush with the side of the tab 320 close to the tab body, that is, the insulating layer 340 starts to extend from the root of the tab 320, it is beneficial to ensure that the insulating layer 340 covers the position where the tab 320 may contact the housing 1, thereby ensuring the insulation protection of the insulating layer 340 for the tab 320. Among them, the direction away from the electrode group body 310 is the positive direction of the Y axis.
[0049] In one embodiment, the insulating layer 340 is sprayed on the tab 320. The insulating layer 340 is processed by spraying, with high production efficiency, strong covering ability and good surface flatness, which is beneficial to improving the insulation performance.
[0050] In one embodiment, an explosion-proof valve 202 is further provided on the cover plate 2. The explosion-proof valve 202 opens when the internal air pressure of the battery reaches a preset value to discharge the high-pressure gas inside the battery and prevent the battery from exploding.
[0051] In one embodiment, a liquid injection hole 203 is further formed on the cover plate 2. The liquid injection hole 203 is used to inject electrolyte into the battery. The rubber plug 204 is detachably engaged with the liquid injection hole 203. When the rubber plug 204 is inserted into the liquid injection hole 203, it is used to seal the liquid injection hole 203, and then an aluminum cover 205 is placed outside the rubber plug 204 to further enhance the protection of the liquid injection hole 203.
[0052] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including: the above-mentioned battery, and the number of the batteries is multiple.
[0053] In one embodiment, the battery is a lithium battery.
[0054] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A battery, characterized in that, Comprising: A housing having an open end; A cover plate disposed at the open end of the housing to enclose the housing, and a terminal post is provided on the cover plate; A pole group located inside the housing, the pole group includes a pole group body and a tab connected thereto. The tab has a free state extending in the Y direction and an assembled state bent in the X direction. When the tab is in the free state, the length of the tab in the Y direction is L; when the tab is in the assembled state, a welding mark is formed on the tab to electrically connect the tab to the terminal post. The dimension of the welding mark in the X direction is W. In the X direction, the distance between the end of the welding mark close to the housing and the inner wall of the housing is C; An insulating layer coated on the surface of the tab facing the housing. When the tab is in the free state, the length a of the insulating layer in the Y direction satisfies the formula: L - W - C + 1mm ≤ a ≤ L - W.
2. The battery according to claim 1, characterized in that, The dimension W of the welding mark in the X direction ranges from: 1mm ≤ W ≤ 6mm.
3. The battery according to claim 1, characterized in that, The thickness of the pole group body is T, and the relationship between the length L of the tab in the Y direction and the thickness T of the pole group body satisfies: T ≤ L ≤ 2T.
4. The battery according to claim 3, characterized in that, The distance C between the end of the welding mark close to the housing and the inner wall of the housing ranges from: 3mm ≤ C ≤ T / 2.
5. The battery according to claim 1, characterized in that, When the tab is in the free state, the length a of the insulating layer in the Y direction ranges from: 3mm ≤ a ≤ 60mm.
6. The battery according to claim 1, characterized in that, When the tab is in the free state, the dimension b of the insulating layer in the X direction ranges from: 0.05mm ≤ b ≤ 0.5mm.
7. The battery according to claim 1, characterized in that, The insulating layer is a ceramic layer.
8. The battery according to claim 1, wherein, When the tab is in the free state, one side of the insulating layer is flush with the side of the tab close to the pole group body and extends in a direction away from the pole group body.
9. The battery according to any one of claims 1 to 8, characterized in that, The insulating layer is sprayed on the tab.
10. A battery pack, characterized in that, Comprising: The battery according to any one of claims 1 to 9.