Square-shell battery and electronic device
By coating a reinforcing layer and designing reinforcing ribs in the negative electrode tab area, the problems of tab wrinkling and folding in prismatic batteries are solved, improving the battery's safety and charge/discharge performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ENVISION AESC JAPAN LTD
- Filing Date
- 2025-05-13
- Publication Date
- 2026-05-05
AI Technical Summary
Existing prismatic batteries, with their multi-layer tabs and ultra-thin current collector designs, are prone to tab wrinkles and folds, affecting charge/discharge performance and safety.
A reinforcing layer is coated in the negative electrode tab area. The width and spacing ratio of the reinforcing layer to the negative electrode active material layer are controlled. Combined with the reinforcing rib design, the support effect of the tab area is improved, and wrinkles and folds are avoided.
This improves the battery's safety and charge/discharge performance, ensuring that the area for welding in the tab region is not occupied by the reinforcing layer, thus avoiding problems such as internal short circuits.
Smart Images
Figure CN224204107U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of secondary battery technology, specifically to a square-shell battery and an electronic device. Background Technology
[0002] Currently, in fields such as electric vehicles, prismatic batteries are increasingly used as vehicle power sources due to their high volumetric energy density. Existing prismatic batteries typically employ a method of folding the tabs together before folding them back together. With increasing demands for energy density and fast charging, prismatic batteries require multiple layers of tabs to accommodate larger capacity cells. During laser welding of these multiple layers of tabs and adapter plates, the outer tabs need to be bent due to the increased tab length, leading to a wider tab area on the current collector. Furthermore, to improve energy density, the current collector is becoming increasingly thinner, and ultra-thin current collectors are prone to wrinkling. Therefore, wrinkles and folds can easily occur during the tab rolling process, affecting process yield. Folding the tabs can also cause reverse insertion and short circuits, impacting the charge / discharge performance and safety of the finished cell. Utility Model Content
[0003] This invention proposes a square-shell battery and electronic device. The reinforcing layer can provide better support and improve the safety performance of the battery while reducing the need for wrinkles and folds in the negative electrode tab area.
[0004] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution.
[0005] This utility model provides a square-shell battery, comprising:
[0006] The housing includes an opening.
[0007] An electrode assembly disposed within the housing and a cover plate assembly sealing the opening;
[0008] The electrode assembly includes a positive electrode, a diaphragm, and a negative electrode. Along a predetermined direction, the electrode assembly includes at least a main body and a negative electrode tab. The negative electrode tab includes a bent portion and a connecting portion. The connecting portion is fixedly connected to the cover plate assembly, and the bent portion is connected between the main body and the connecting portion.
[0009] The negative electrode sheet includes a negative current collector, the negative current collector includes a negative electrode tab region and a negative electrode active region located on at least one side of the negative electrode current collector, and a negative electrode active material layer is coated on the negative electrode active region; along a predetermined direction, a reinforcing layer is coated on at least one side of at least a portion of the negative electrode tab region, the width of the negative electrode tab region is W1 mm, the width of the reinforcing layer is W2 mm, and the condition 2.5≤W1 / W2≤7.5 is met;
[0010] The reinforcing layer covers at least a portion of the bent portion.
[0011] In one embodiment of this utility model, along the preset direction, there is a preset distance G mm between the negative electrode active material layer and the reinforcing layer, satisfying 22≤W1 / G≤400.
[0012] In one embodiment of this utility model, the preset spacing is 0.1mm-1.1mm.
[0013] In one embodiment of this utility model, along the preset direction, the width of the negative electrode active material layer is W3mm, satisfying 3≤W3 / W1≤11.
[0014] In one embodiment of this utility model, the ratio of the thickness of the reinforcing layer on one side to the thickness of the negative electrode current collector is 1-6; or,
[0015] The thickness of the negative electrode current collector is 4μm-5.5μm.
[0016] In one embodiment of this utility model, the grayscale value of the reinforcing layer is 0-110.
[0017] In one embodiment of the present invention, a portion of the negative electrode active material layer covers at least a portion of the surface of the negative electrode tab along the preset direction; or, a transition region is provided between the negative electrode tab and the negative electrode active material layer coating area, and the reinforcing layer is located on a portion of the transition region and a portion of the surface of the negative electrode tab.
[0018] In one embodiment of this utility model, the negative electrode tab further includes a plurality of reinforcing ribs, and the reinforcing ribs are stamped and formed by the negative electrode tab. The reinforcing ribs are arranged in at least one of the following shapes: dot-shaped, strip-shaped, wavy, or zigzag-shaped. The ratio of the width of the maximum overlap position of the reinforcing ribs and the reinforcing layer to the width of the reinforcing layer is 0.1-1.
[0019] In one embodiment of this utility model, the electrode assembly is covered with a first adhesive tape. The first adhesive tape is disposed on the side of the negative electrode tab facing away from the cover plate assembly. The first adhesive tape includes a first adhesive area, a second adhesive area, and a non-adhesive area located between the first adhesive area and the second adhesive area. The first adhesive area covers the main body, and the second adhesive area covers the connecting portion. In the thickness direction of the electrode assembly, the orthogonal projection of the reinforcing layer is completely located within the non-adhesive area.
[0020] This utility model also provides an electronic device, including the aforementioned prismatic battery.
[0021] In summary, the prismatic battery and electronic device provided by this utility model can provide better support when the width of the negative electrode tab area is large, preventing wrinkles or folds in the negative electrode tab area. It also prevents the reinforcing layer from being too wide and encroaching on the welding area of the negative electrode tab area, ensuring the size of the welding area for the negative electrode tab area and improving the safety performance of the prismatic battery. Furthermore, when assembling a prismatic battery using this electrode sheet, the negative electrode tab area is bent, preventing insertion problems and avoiding short circuits and other related failures. Attached Figure Description
[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This is a schematic diagram of a square-shell battery in one embodiment.
[0024] Figure 2 This is a schematic diagram of an electrode assembly in one embodiment.
[0025] Figure 3 This is a schematic diagram of the electrode assembly in another embodiment.
[0026] Figure 4 This is a schematic diagram of the negative electrode sheet in one embodiment.
[0027] Figure 5 For along Figure 1 A cross-sectional view of the negative electrode in the AA direction.
[0028] Figure 6 This is a schematic diagram of the negative electrode tab on the electrode sheet in one embodiment.
[0029] Figure 7 This is a schematic diagram of the negative electrode tab and reinforcing rib on the electrode sheet in one embodiment.
[0030] Figure 8 This is a schematic diagram of the negative electrode tab on the electrode sheet in another embodiment.
[0031] Figure 9 This is a schematic diagram of the negative electrode tab and reinforcing rib on the electrode sheet in another embodiment.
[0032] Figure 10 This is a schematic diagram of the positive electrode sheet in one embodiment.
[0033] Figure 11 This is a schematic diagram of the positive electrode tab on the positive electrode plate in one embodiment.
[0034] Figure 12 This is a schematic diagram of the positive electrode tab on the positive electrode plate in another embodiment.
[0035] Figure 13 This is a schematic diagram of a portion of the electrode assembly in one embodiment.
[0036] Label Explanation:
[0037] 10. Housing; 1011. Opening; 11. Cover assembly; 12. First electrode post; 13. Second electrode post; 14. Explosion-proof valve; 15. Injection port; 20. Electrode assembly; 100. Negative electrode plate; 101. Negative electrode active area; 102. Negative electrode tab area; 110. Negative electrode current collector; 120. Negative electrode active material layer; 130. Reinforcing layer; 140. Negative electrode tab; 150. Reinforcing rib; 160. Transition region; 200, positive electrode sheet; 210, positive electrode current collector; 220, positive electrode active material layer; 230, positive electrode tab region; 240, positive electrode tab; 241, connection region; 1, main body; 111, connection part; 112, bending part; 1112, adapter piece; 30, first adhesive tape; 31, first adhesive region; 32, non-adhesive region; 33, second adhesive region; 300, diaphragm; 40, second adhesive tape. Detailed Implementation
[0038] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.
[0039] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this solution. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effectiveness and purpose achieved by this solution, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms used in this specification such as "upper," "lower," "left," "right," "middle," "below," "below," "first," "second," and "one," etc., are merely for clarity of description and are not intended to limit the scope of implementation of this solution. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the implementation of this solution.
[0040] The technical solution of this utility model will be further described in detail below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0041] This application provides an electronic device including at least one prismatic battery for providing electrical energy. The electronic device can be a vehicle, mobile phone, portable device, laptop, ship, spacecraft, electric toy, or power tool, etc. In one embodiment of this invention, the vehicle is, for example, a new energy vehicle, which can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. The spacecraft includes airplanes, rockets, space shuttles, and spacecraft, etc. The electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. The power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.
[0042] Please see Figure 1 As shown, this application also provides a prismatic battery that can be used in the aforementioned electronic device. The prismatic battery includes a housing 10, an electrode assembly, and a cover assembly 11. The housing 10 includes an opening 1011, and the electrode assembly is disposed inside the housing 10 through the opening 1011. The cover assembly 11 seals the opening 1011 of the housing 10. This invention does not limit the type of prismatic battery. The prismatic battery can be, for example, a primary battery or a secondary battery, such as a sodium-ion secondary battery or a lithium-ion secondary battery. In this embodiment, a lithium-ion secondary battery is used as an example for illustration.
[0043] Please see Figures 1 to 3As shown, in one embodiment of this utility model, the prismatic battery includes, for example, a housing 10, a cover assembly 11, and an electrode assembly 20 disposed within the housing 10. The tabs of the electrode assembly 20 are electrically connected to the terminals on the housing 10. The shape of the electrode assembly 20 matches the shape of the housing 10, and the material of the housing 10 is, for example, an aluminum shell, a steel shell, or a flexible shell. The housing 10 is a receiving cavity with an upper opening for accommodating the electrode assembly 20. Specifically, after the electrode assembly 20 is placed in the housing 10 through the upper opening, the housing 10 is sealed using the cover assembly 11. The cover assembly 11 is provided with a first terminal 12, a second terminal 13, an explosion-proof valve 14, and an injection hole 15, etc. Electrolyte is injected through the injection hole 15, and then the injection hole 15 is sealed. The first terminal 12 and the second terminal 13 have opposite polarities; the first terminal 12 and the second terminal 13 are either positive or negative electrodes, and this utility model does not limit the specific polarity category of the first terminal 12 and the second terminal 13. The first electrode post 12 is electrically connected to the tabs of the same polarity on the electrode assembly 20, and the second electrode post 13 is electrically connected to the tabs of the same polarity on the electrode assembly 20. In this embodiment, the positions of the first electrode post 12 and the second electrode post 13 are not limited; they can be located at the same end of the housing or at both ends of the housing, depending on the position of the tabs on the electrode assembly 20 or the design requirements.
[0044] Please see Figure 1 As shown, in one embodiment of this utility model, when the first pole 12 and the second pole 13 are disposed at one end of the housing 10, the explosion-proof valve 14 and the injection port 15 are disposed between the first pole 12 and the second pole 13. The explosion-proof valve 14 is, for example, disposed at the middle position of the first pole 12 and the second pole 13, and is respectively at a preset distance from the first pole 12 and the second pole 13. The injection port 15 is disposed between the explosion-proof valve 14 and the first pole 12, or between the explosion-proof valve 14 and the second pole 13. That is, the explosion-proof valve 14, the injection port 15, the first pole 12, and the second pole 13 are arranged alternately. The explosion-proof valve 14 can open its venting function when the battery cell is working normally, allowing airflow inside and outside the battery cell while preventing the flow of particulate matter. When thermal runaway occurs in the battery cell, and the pressure difference inside and outside the battery cell reaches the preset explosion-proof value, the explosion-proof valve opens, allowing both gas and solids to be discharged from the inside of the battery cell to the outside, thus improving the safety performance of the battery cell.
[0045] Please see Figures 2 to 3As shown, in one embodiment of this utility model, the electrode assembly 20 includes a negative electrode 100, a positive electrode 200, and a separator 300. The separator 300 is disposed between the positive electrode 200 and the negative electrode 100 to prevent contact between the positive electrode 200 and the negative electrode 100, which could lead to safety issues. An electrolyte (not shown in the figure) is filled between the negative electrode 100, the positive electrode 200, and the separator 300, as well as between the electrode assembly 20 and the housing, to conduct ions between the positive and negative electrodes. The electrolyte can be any suitable lithium-ion battery electrolyte. This application does not specifically limit the stacking method of the positive and negative electrodes; the specific method is selected according to the manufacturing requirements.
[0046] In one embodiment of this invention, the electrolyte includes, for example, an organic solvent and a lithium salt. The organic solvent is selected from one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl acetate (EA), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), or diethyl carbonate (DEC). The lithium salt is selected from, for example, one or more of lithium bis(fluorosulfonyl)imide (LiFSi), lithium difluorophosphate (LiPO2F2), lithium hexafluorophosphate (LiPF6), or lithium tetrafluoroborate (LiBF4). In one embodiment of this invention, the lithium salt is selected from, for example, lithium hexafluorophosphate, and the organic solvent is selected from, for example, a mixture of ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, and propylene carbonate. Ethylene carbonate, methyl ethyl carbonate, diethyl carbonate, and propylene carbonate are mixed, for example, in a volume ratio of 1:1:1:1. The thoroughly dried LiPF6 is dissolved in the mixed organic solvent in an argon-atmosphere glove box with a water content of less than 10 ppm. After thorough mixing, an electrolyte is obtained, wherein the concentration of LiPF6 is, for example, 1 mol / L.
[0047] Please see Figures 2 to 3As shown, in one embodiment of this utility model, the negative electrode 100 and the positive electrode 200 are formed into an electrode assembly 20 by means of winding or stacking, for example, a multilayer stack or a Z-shaped stack, etc., and this application does not impose specific limitations. The separator 300 is, for example, a polyethylene film (PE), a polypropylene film (PP), a glass fiber film, a polyethylene film, or a composite film, etc., and in this application, the thickness of the separator 300 is not limited, as long as it meets the usage requirements.
[0048] Please see Figure 4 As shown, in one embodiment of this utility model, the negative electrode sheet 100 includes a negative electrode current collector 110, which includes a negative electrode tab region 102 and a negative electrode active region 101 located on at least one side of the negative electrode current collector 110. A negative electrode active material layer 120 is coated on the negative electrode active region 101. A reinforcing layer 130 is coated on at least one side of at least a portion of the negative electrode tab region 102 along a predetermined direction Y. The direction perpendicular to the predetermined direction Y is defined as the vertical direction X. In the vertical direction X, the length of the reinforcing layer 130 is equal to the length of the negative electrode active material layer 120. Along the predetermined direction Y, the width of the negative electrode tab region 102 is W1 mm, and the width of the reinforcing layer 130 is W2 mm, satisfying 2.5 ≤ W1 / W2 ≤ 7.5. In a specific embodiment of this utility model, the width W2 of the reinforcing layer 130 is, for example, 3 mm to 12 mm. When the width of the negative electrode tab area 102 is large, there is a high risk of folding and wrinkling of the negative electrode tab area 102 during die cutting and winding. By controlling the ratio of the width of the negative electrode tab area 102 to the width of the reinforcing layer 130, when the width of the negative electrode tab area 102 is large, the reinforcing layer 130 can play a supporting role and avoid folding and wrinkling. When the width of the negative electrode tab area 102 is small, it can also prevent the width of the reinforcing layer 130 from occupying the welding area of the negative electrode tab area 102 used for connection with the external electrode post, thus affecting the welding of the negative electrode tab area 102.
[0049] Please see Figure 4As shown, in one embodiment of this utility model, a preset distance, denoted as G mm, is provided between the negative electrode active material layer 120 and the reinforcing layer 130 along a preset direction Y, satisfying 22 ≤ W1 / G ≤ 400. In a specific embodiment of this utility model, the preset distance G is, for example, 0.1 mm to 1.1 mm. By controlling the ratio of W1 / G, within a suitable range of the width of the negative electrode tab region 102 and the preset distance, it is possible to prevent the preset distance from being too large, which would weaken the effect of the reinforcing layer and may result in insufficient welding area for the negative electrode tab region 102 to connect with the external electrode post. By balancing the width of the negative electrode tab region 102 and the preset distance, it is possible to avoid the preset distance being too small, which would lead to the reinforcing layer 130 and the negative electrode active material layer 120 fusing together and causing bulging, etc. Thus, the boundary between the reinforcing layer 130 and the negative electrode active material layer 120 is clear, which can improve the performance of the prismatic battery and reduce safety hazards.
[0050] Please see Figure 4 As shown, in one embodiment of this utility model, the width of the negative electrode active material layer 120 along the preset direction Y is W3 mm, satisfying 3≤W3 / W1≤11. In a specific embodiment of this utility model, the width W1 of the negative electrode tab region 102 is, for example, 30mm-40mm. By controlling the ratio of the width of the negative electrode active material layer 120 to the width of the negative electrode tab region 102, the widths of both the negative electrode active material layer 120 and the negative electrode tab region 102 can be balanced while setting a reinforcing layer. This facilitates bending of the uncoated area to connect electrically with the electrode post, avoids folding and wrinkling, and balances the mass energy density of the prismatic battery.
[0051] Please see Figure 4 and Figure 5As shown, in one embodiment of this utility model, the negative electrode current collector 110 is, for example, a copper foil. At least one side of the negative electrode current collector 110 includes a negative electrode active material layer 120 and a reinforcing layer 130 disposed adjacent to each other along a predetermined direction Y. In another embodiment of this utility model, negative electrode active material layers 120 are disposed on both sides of the negative electrode current collector 110, and reinforcing layers 130 spaced apart from the negative electrode active material layers 120 are disposed on both sides of the negative electrode current collector 110 along a predetermined direction Y. That is, the negative electrode current collector 110 has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material layer 120 and the reinforcing layer 130 are simultaneously disposed spaced apart on one surface of the negative electrode current collector 110; or the negative electrode active material layer 120 is simultaneously disposed on both surfaces of the negative electrode current collector 110, and the reinforcing layer 130 is disposed on one surface of the negative electrode current collector 110; or the negative electrode active material layer 120 and the reinforcing layer 130 are simultaneously disposed spaced apart on both surfaces of the negative electrode current collector 110. In this embodiment, the thickness of the reinforcing layer 130 on the negative electrode current collector side is H μm, and the thickness of the negative electrode current collector 110 is h μm, satisfying 1 ≤ H / h ≤ 6. The ratio of the thickness of the negative electrode active material layer 120 on the negative electrode current collector side to the thickness of the negative electrode current collector 110 is, for example, 5.5-34. In a specific embodiment of this invention, the thickness h of the negative electrode current collector 110 is, for example, 4 μm-5.5 μm, and the thickness of the negative electrode active material layer 120 on one side is, for example, 30 μm-150 μm. Because the thinner the negative electrode current collector, the easier it is to wrinkle during die-cutting and winding, especially for thin materials with a thickness ≤ 5.5 μm, setting appropriate thicknesses for the negative electrode active material layer and the negative electrode current collector, and matching the design of the reinforcing layer, can avoid wrinkling of the negative electrode current collector, maintain the strength of the negative electrode tab area, and avoid the problem of wavy edges caused by laser cutting at the junction of the negative electrode active material layer and the negative electrode tab area. At the same time, the bottom support of the negative electrode tab area is improved so that the negative electrode tab formed later will not be inserted into the negative electrode tab when it is bent.
[0052] Please see Figure 4 and Figure 5As shown, in one embodiment of this utility model, the negative electrode active material layer 120 includes, for example, a negative electrode active material, a negative electrode binder, a thickener, and a negative electrode conductive agent. The negative electrode active material is selected from, for example, any one or a combination of at least two of soft carbon, hard carbon, artificial graphite, silicon, silicon oxide compounds, silicon carbide compounds, or lithium titanate. The negative electrode binder is selected from, for example, any one or more of polypropylene, polyacrylic acid and its derivatives, or styrene-butadiene rubber. The negative electrode conductive agent is selected from, for example, any one or more of conductive carbon black (Super-P, SP), acetylene black, carbon nanotubes, and graphene. The thickener is selected from, for example, sodium carboxymethyl cellulose. The uniform thickness of the negative electrode active material layer 120 on the negative electrode current collector 110 improves the charging and discharging consistency of the prismatic battery. This application does not limit the mass ratio of the negative electrode active material, negative electrode binder, thickener, and negative electrode conductive agent; the selection is based on the preparation requirements.
[0053] Please see Figure 4 and Figure 5As shown, in one embodiment of this utility model, the reinforcing layer 130 includes, for example, ceramic particles, an aqueous binder, and a color developer. The ceramic particles include, for example, at least one of boehmite, alumina, titanium dioxide, zirconium dioxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride, or magnesium nitride. The aqueous binder includes, for example, at least one of polyacrylic acid (PAA), polymerized styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), polyacrylamide (PAM), methylcellulose and its salts, chitosan and its salts, and alginate and its salts. The color developer includes, for example, at least one of carbon black, chromium oxide green, cobalt green, cobalt blue, iron blue, cadmium red, carbon black, or iron oxide red. By incorporating a color developer within the reinforcing layer 130, the grayscale value of the reinforcing layer 130 can be set to, for example, 0-110. This increases the color difference between the reinforcing layer 130 and the negative electrode current collector 110, and the grayscale value of the reinforcing layer is lower than that of the negative electrode current collector. During the die-cutting process of forming the negative electrode tab, this facilitates the identification of the size and position of the reinforcing layer 130 by a charge-coupled device (CCD) detector. Furthermore, the reinforcing layer 130 can absorb laser energy, reducing laser reflection and scattering, thus concentrating the laser energy and reducing die-cutting power and energy consumption. It also makes the cut edges less prone to burrs, thereby reducing short circuits caused by burrs. By selecting a water-based binder, the negative electrode production line can be made to eliminate the need for organic gas recovery equipment during the preparation of the reinforcing layer 130. The ceramic particles can also provide support for the reinforcing layer 130, thereby improving the design of the width of the negative electrode tab region 102 and achieving a larger width of the negative electrode tab region 102. At the same time, it improves the insulation of the reinforcing layer 130 and prevents leakage.
[0054] Please see Figure 4 and Figure 5 As shown, in one embodiment of this invention, the mass ratio of ceramic particles, water-based binder, and colorant in the reinforcing layer 130 is, for example, 10-20:75-90:0.5-5. The high content of water-based binder improves the adhesion between the reinforcing layer 130 and the negative electrode current collector 110, preventing the reinforcing layer 130 from peeling off during bending of the subsequently formed negative electrode tab. In one embodiment of this invention, the peel force between the reinforcing layer 130 and the negative electrode current collector 110 is greater than 300 N / m during the bending process of the negative electrode tab.
[0055] Please see Figure 5As shown, in one embodiment of this invention, when forming the negative electrode active material layer 120 and the reinforcing layer 130, the negative electrode active material, negative electrode binder, thickener, and negative electrode conductive agent are dispersed in water according to a mass ratio to obtain a negative electrode slurry. Ceramic particles, an aqueous binder, and a color developer are dispersed in water according to a mass ratio to obtain a reinforcing layer slurry. During the coating process, the negative electrode slurry and the reinforcing layer slurry are simultaneously coated onto the negative electrode current collector 110 and dried to obtain the negative electrode active material layer 120 and the reinforcing layer 130.
[0056] Please see Figure 6 and Figure 8 As shown, in one embodiment of this utility model, after forming the negative electrode active material layer 120 and the reinforcing layer 130, a negative electrode tab 140 is obtained by die-cutting a portion of the negative electrode tab region 102 or by die-cutting the negative electrode tab region 102 and a portion of the negative electrode active region 101. The die-cutting stop position is denoted as the shoulder B of the negative electrode tab 140, and the negative electrode tab 140 extends from shoulder B to the side of the negative electrode tab region 102 away from the negative electrode active material layer 120. By providing a transition region 160, the laser energy for die-cutting can be reduced, thus reducing energy consumption. Specifically, compared to die-cutting to a portion of the area with the negative electrode active material layer, the laser energy is lower, reducing laser power, minimizing foil leakage, improving the energy density and cycle performance of the prismatic battery, and enhancing safety performance.
[0057] Please see Figure 6 and Figure 7 As shown, in one embodiment of this invention, a portion of the negative electrode active material layer 120 covers at least a portion of the surface of the negative electrode tab 140 along a predetermined direction Y. In this case, the height of the negative electrode tab 140 includes the dimensions of the negative electrode active material layer that may extend to both sides of the negative electrode tab 140.
[0058] Please see Figure 8 and Figure 9 As shown, in another embodiment of this utility model, the negative electrode sheet 100 further includes a negative electrode tab 140, a transition region 160 is provided between the negative electrode tab 140 and the negative electrode active region 101, and a reinforcing layer 130 is located on a portion of the transition region 160 and a portion of the surface of the negative electrode tab 140. In this case, the height of the negative electrode tab includes the size of the reinforcing layer located on the portion of the negative electrode tab 140.
[0059] Please see Figures 7 to 9As shown, in one embodiment of this utility model, the negative electrode tab 140 further includes a plurality of reinforcing ribs 150, and the reinforcing ribs 150 are stamped and formed by the negative electrode tab 140. The reinforcing ribs 150 are arranged on the negative electrode tab 140 in at least one shape such as dot, strip, wave, or zigzag, and are spaced apart from each other along a preset direction and / or a vertical direction. When the reinforcing ribs 150 are distributed in a strip shape, the reinforcing ribs 150 are similar to multiple parallel long strips. The ratio of the width (W4 mm) of the maximum overlap position of the reinforcing ribs 150 and the reinforcing layer 130 to the width (W2 mm) of the reinforcing layer 130 is 0.1-1. The maximum distance from the reinforcing rib 150 located on the reinforcing layer 130 away from the preset direction to the side of the reinforcing layer 130 away from the negative electrode active material layer 120 is defined as W4. When W4 / W2 is 1, it indicates that the reinforcing rib 150 at least coincides with the side of the reinforcing layer 130 near the negative electrode active material layer 120, or that part of the reinforcing rib 150 is located within a predetermined distance between the reinforcing layer 130 and the negative electrode active material layer 120. In a specific embodiment of this utility model, after the negative electrode tab 140 is formed, the reinforcing rib 150 is obtained, for example, by stamping the negative electrode current collector 110 in the region of the negative electrode tab 140. In other embodiments, the reinforcing rib 150 can also be made in other ways, for example, the reinforcing rib 150 can be formed separately and then fixed to the negative electrode current collector 110. By controlling the ratio of W4 / W2 within a suitable range, the strength of the reinforcing layer can be improved, the wrinkles of the negative electrode tab can be reduced, thereby further increasing the width of the negative electrode tab region 102, thus accommodating more layers of negative electrode tabs and reducing the direct current resistance (DCR) of the prismatic battery.
[0060] Please see Figure 10 As shown, in one embodiment of this utility model, the positive electrode 200 includes a positive current collector 210 and a positive active material layer 220 coated on at least one surface of the positive current collector 210. That is, the positive current collector 210 has two surfaces opposite each other in its own thickness direction, and the positive active material layer 220 can be disposed on either or both of the two surfaces of the positive current collector 210. The positive current collector 210 can be an aluminum foil current collector, with a thickness of, for example, 5 μm-20 μm, and further, a thickness of, for example, 10 μm-15 μm. The positive current collector 210 can also be a composite current collector, which includes a polymer matrix and aluminum layers located on the upper and lower surfaces of the polymer matrix. The polymer matrix can be selected from polyethylene terephthalate, polypropylene, polyimide, polystyrene, or polyamide, etc.
[0061] Please see Figure 10As shown, in one embodiment of this utility model, on the positive current collector 210, the area coated with the positive active material layer 220 is defined as the positive electrode sheet area, and the area of the positive current collector 210 without the positive active material layer 220 is defined as the positive electrode tab area 230, used to form the positive electrode tab. The positive electrode sheet area and the positive electrode tab area 230 are arranged adjacent to each other. The positive active material layer 220 includes a positive active material, a positive conductive agent, and a positive binder. The positive active material can be selected from one or more combinations of lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, lithium titanate, lithium nickel cobalt manganese aluminum oxide, lithium iron phosphate, and lithium manganese iron phosphate. The positive conductive agent is selected, for example, from one or a combination of two or more of conductive carbon black, acetylene black, nano-metal powder, graphene, carbon nanotubes, or carbon nanofibers in any proportion. The positive electrode binder is selected from one or more of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene, or polytetrafluoroethylene. This invention does not limit the thickness of the positive electrode active material layer 220; the thickness is selected based on the design requirements of the prismatic battery.
[0062] Please see Figure 11 and Figure 12 As shown, in one embodiment of the present invention, the positive electrode sheet 200 includes a plurality of positive electrode tabs 240, and a portion of the positive electrode active material layer 220 covers at least a portion of the surface of the positive electrode tabs 240; or a connection region 241 is provided between the positive electrode tabs 240 and the positive electrode active material layer 220, the connection region 241 is located within the positive electrode tab region 230, that is, the positive electrode active material layer 220 is not provided on the connection region 241, and the positive electrode active material layer 220 does not cover the positive electrode tabs 240.
[0063] Please see Figure 1 , Figure 7 , Figure 9 and Figure 13As shown, in one embodiment of this utility model, the negative electrode 100, the positive electrode 200, and the separator 300 are formed into an electrode assembly 20 by means of winding or stacking, for example. The electrode assembly 20 includes a main body 1 and a negative electrode tab 140 and a positive electrode tab 240 located at one end of the main body 1. The main body 1 is formed by laminating the shoulder B of the negative electrode tab. The two electrode assemblies 20 are disposed opposite to each other in the housing 10. Each electrode assembly 20 has a negative electrode tab 140 and a positive electrode tab 240 at the end facing the cover plate assembly 11. The negative electrode tab 140 and the positive electrode tab 240 can be connected to the cover plate assembly 11 through corresponding adapter pieces 1112. In this configuration, the positive electrode tabs 240 of the two electrode assemblies 20 are welded together, and the negative electrode tabs 140 of the two electrode assemblies 20 are welded together. The positive electrode tabs 240 and negative electrode tabs 140 of the two electrode assemblies 20 are welded correspondingly and then welded to the adapter piece 1112. After that, the two electrode assemblies 20 are bent relative to each other and then installed into the housing 10. The negative electrode tab 140 includes a connecting portion 111 and a bending portion 112. The connecting portion 111 is fixedly connected to the adapter piece 1112, and the bending portion 112 is connected between the main body 1 and the connecting portion 111. The reinforcing layer 130 covers at least a portion of the bending portion 112. A first adhesive tape 30 covers the negative electrode tab 140, located on the side of the negative electrode tab 140 facing away from the cover plate assembly 11, to protect the negative electrode tab 140. The first adhesive tape 30 includes a first adhesive area 31, a second adhesive area 33, and a non-adhesive area 32 located between the first adhesive area 31 and the second adhesive area 33. The first adhesive area 31 covers the main body 1, and the second adhesive area 33 covers the connecting portion 111. In the thickness direction of the electrode assembly, the orthogonal projection of the reinforcing layer 130 lies entirely within the non-adhesive area 32, thereby preventing the reinforcing layer from falling off when the tab is static or during tab assembly. A second adhesive tape 40 covers the positive electrode tab 240, located on the side of the positive electrode tab 240 facing away from the cover plate assembly 11, to protect the positive electrode tab 240. The tape improves the safety of the foil leakage, and the non-adhesive area covering the reinforcing layer prevents the reinforcing layer from falling off. The tape provides support and can prevent the negative electrode tab from being inserted into or torn.
[0064] The present invention will be explained in more detail below by referring to embodiments, which should not be construed as limiting. Appropriate modifications may be made within the scope of the present invention, and all such modifications shall fall within the technical scope of the present invention.
[0065] Example 1
[0066] Preparation of the negative electrode sheet: Boehmite, polyacrylic acid, and carbon black are mixed in a mass ratio of 20:75:5, deionized water is added, and the mixture is stirred evenly under vacuum to obtain a reinforcing layer slurry. Artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, and styrene-butadiene rubber are mixed in a mass ratio of 96:1:1:2, deionized water is added, and the mixture is stirred evenly under vacuum to obtain a negative electrode slurry. The negative electrode slurry and reinforcing layer slurry are simultaneously coated onto a 6μm thick copper foil, then transferred to an oven for drying. After processes such as rolling, slitting, die-cutting, and sheet cutting, the negative electrode sheet is obtained. Notably, during the formation of the negative electrode tab, the shoulder of the negative electrode tab is located within the reinforcing layer, i.e., a transition zone is established. The width of the negative electrode active material layer coating area is 210 mm, the width of the negative electrode tab area is 30 mm, the width of the reinforcing layer is 12 mm, the thickness of the reinforcing layer is 18 μm, the preset spacing between the reinforcing layer and the negative electrode active material layer is 0.6 mm, that is, the ratio of the width of the negative electrode tab area to the width of the reinforcing layer is 2.5, the ratio of the width of the negative electrode tab area to the preset spacing is 50, the ratio of the thickness of the reinforcing layer to the thickness of the negative electrode current collector is 3, the ratio of the width of the negative electrode active material layer to the width of the negative electrode tab area is 7, and the ratio of the width of the maximum overlap position of the reinforcing rib and the reinforcing layer to the width of the reinforcing layer is 0.5.
[0067] Preparation of positive electrode: LiNi 08 Co 0.1 Mn 0.1 O2, acetylene black, and polyvinylidene fluoride were mixed in a mass ratio of 97:1:2, and N-methylpyrrolidone was added. The mixture was stirred under vacuum until the system was homogeneous to obtain a positive electrode slurry. The positive electrode slurry was uniformly coated onto aluminum foil, then air-dried at room temperature and transferred to an oven for drying. After cold pressing, edge trimming, cutting, and slitting, the positive electrode sheet was obtained.
[0068] Preparation of electrolyte: Ethylene carbonate, methyl ethyl carbonate, diethyl carbonate and propylene carbonate are mixed in a volume ratio of 1:1:1:1. In an argon atmosphere glove box with a water content of less than 10 ppm, fully dried LiPF6 is dissolved in the mixed organic solvent and mixed evenly to obtain the electrolyte. The concentration of LiPF6 is, for example, 1 mol / L.
[0069] Selection of diaphragm: 9μm thick polyethylene was used as the diaphragm.
[0070] Fabrication of a prismatic battery: The positive electrode, separator, and negative electrode are stacked sequentially and wound, with the separator positioned between the positive and negative electrodes to act as a separator. Except for the innermost and outermost rings, each ring of the negative electrode has a negative electrode tab, resulting in a wound bare cell. The bare cell is then placed in an aluminum casing, a top cover assembly is assembled, electrolyte is injected, and the casing is sealed to obtain a lithium-ion prismatic battery.
[0071] Example 2
[0072] The width of the reinforcing layer is 6mm, that is, the ratio of the width of the negative electrode tab area to the width of the reinforcing layer is 5. The rest of the operation is the same as in Example 1.
[0073] Example 3
[0074] The width of the reinforcing layer is 4mm, that is, the ratio of the width of the negative electrode tab area to the width of the reinforcing layer is 7.5. The rest of the operation is the same as in Example 1.
[0075] Example 4
[0076] The width of the negative electrode tab area is 40mm, and the width of the reinforcing layer is 8mm, that is, the ratio of the width of the negative electrode tab area to the width of the reinforcing layer is 5. The rest of the operation is the same as in Example 1.
[0077] Example 5
[0078] The width of the negative electrode tab region is 40mm, the preset spacing between the reinforcing layer and the negative electrode active material layer is 0.1mm, the ratio of the width of the negative electrode tab region to the preset spacing is 400, and the rest of the operation is the same as in Example 2.
[0079] Example 6
[0080] The preset spacing between the reinforcing layer and the negative electrode active material layer is 1.1 mm, and the ratio of the width of the negative electrode tab region to the preset spacing is 27.3. The rest of the operation is the same as in Example 2.
[0081] Example 7
[0082] The thickness of the reinforcing layer is 6 μm, and the ratio of the thickness of the reinforcing layer to the thickness of the negative electrode current collector is 1. The rest of the operation is the same as in Example 2.
[0083] Example 8
[0084] The thickness of the reinforcing layer is 36 μm, and the ratio of the thickness of the reinforcing layer to the thickness of the negative electrode current collector is 6. The rest of the operation is the same as in Example 2.
[0085] Example 9
[0086] The thickness of the negative electrode current collector is 5.5 μm, the thickness of the reinforcing layer is 16.5 μm, the ratio of the thickness of the reinforcing layer to the thickness of the negative electrode current collector is 3, and the rest of the operation is the same as in Example 2.
[0087] Example 10
[0088] The thickness of the negative electrode current collector is 4.5 μm, the thickness of the reinforcing layer is 13.5 μm, the ratio of the thickness of the reinforcing layer to the thickness of the negative electrode current collector is 3, and the rest of the operation is the same as in Example 2.
[0089] Example 11
[0090] The thickness of the negative electrode current collector is 4 μm, the thickness of the reinforcing layer is 12 μm, the ratio of the thickness of the reinforcing layer to the thickness of the negative electrode current collector is 3, and the rest of the operation is the same as in Example 2.
[0091] Comparative Example 1
[0092] The width of the reinforcing layer is 15mm, that is, the ratio of the width of the negative electrode tab area to the width of the reinforcing layer is 2. The rest of the operation is the same as in Example 1.
[0093] Comparative Example 2
[0094] The width of the reinforcing layer is 3.5 mm, which means that the ratio of the width of the negative electrode tab area to the width of the reinforcing layer is 8.6. The rest of the operation is the same as in Example 1.
[0095] Comparative Example 3
[0096] The preset spacing between the reinforcing layer and the negative electrode active material layer is 1.4 mm, and the ratio of the width of the negative electrode tab region to the preset spacing is 21.4. The rest of the operation is the same as in Example 2.
[0097] Comparative Example 4
[0098] The preset spacing between the reinforcing layer and the negative electrode active material layer is 0.05 mm, and the ratio of the width of the negative electrode tab region to the preset spacing is 600. The rest of the operation is the same as in Example 2.
[0099] In one embodiment of this invention, to obtain the negative electrode tab wrinkling performance, after obtaining the bare cell, the distance from the side of each negative electrode tab furthest from the active material layer to the active material layer is measured using a camera. The difference between this distance and the designed value of the negative electrode tab area width is calculated (for design values after disassembling a prismatic battery, the maximum value of the uncoated area width is used for negative electrode tabs of equal height). The average value of the difference is then obtained and defined as the negative electrode tab deviation value (if the deviation value of the negative electrode tab area is obtained, the distance from the side of each negative electrode tab area furthest from the active material layer to the active material layer is obtained using a camera). The negative electrode tab deviation value is used to characterize the negative electrode tab wrinkling performance; the smaller the negative electrode tab deviation value, the fewer wrinkles occur on the negative electrode tab.
[0100] In one embodiment of this utility model, in order to obtain the folding situation of the negative electrode tab, after obtaining the bare cell, the orthogonal projection area of each negative electrode tab on the plane where the negative current collector is located is obtained by a CCD camera, denoted as S1, and the orthogonal projection area of each negative electrode tab on the plane where the negative current collector is located after being flattened is denoted as S2 (if the folding situation of the negative electrode tab area is obtained, the orthogonal projection area of the negative electrode tab area of each layer on the plane where the negative current collector is located, and the orthogonal projection area of each layer of negative electrode tab area on the plane where the negative current collector is located after being flattened are obtained by a CCD camera). The calculation error is calculated as (S2-S1) / S2×100%. A negative electrode tab with an error greater than 5% is defined as a folding of the negative electrode tab. The ratio of the number of layers with folding of the negative electrode tab to the total number of layers of negative electrode tabs is calculated.
[0101] In one embodiment of this utility model, after obtaining the negative electrode sheet, it is observed whether the reinforcing layer and the negative electrode active material layer are fused. The fused state is the fusion of the material of the negative electrode active material layer in the reinforcing layer area. The unfused appearance state is that the reinforcing layer and the negative electrode active material layer are completely separated, and the corresponding spacing is relatively uniform.
[0102] In one embodiment of this utility model, after disassembling the square-shell battery cells of Examples 1-11 and Comparative Examples 1-4, the actual number of negative electrode tab welding layers is observed, and the ratio of the actual number of negative electrode tab welding layers to the designed number of negative electrode tabs is calculated (if the number of welding layers in the negative electrode tab area is obtained, the actual number of welding layers and the designed number of layers in the negative electrode tab area are obtained).
[0103] Table 1. Some characteristics and performance of the negative electrode sheets in Examples 1-4 and Comparative Examples 1-2
[0104]
[0105] Please refer to Table 1. Comparing Examples 1-4 and Comparative Examples 1-2, it can be seen that when the width of the reinforcing layer is small, i.e., when W1 / W2 is large, the deviation value of the negative electrode tab area is large, and the proportion of folds in the negative electrode tab area is large, indicating that there are more wrinkles and folds in the negative electrode tab area. As the width of the reinforcing layer gradually increases, the deviation value of the negative electrode tab area gradually decreases, and the proportion of folds in the negative electrode tab area is less than 0.5%, indicating that increasing the width of the reinforcing layer can reduce the wrinkles and folds in the negative electrode tab area. When the width of the reinforcing layer is too large, i.e., W1 / W2 is less than 2.5, welding in the area used for welding in the negative electrode tab area and the adapter piece can lead to cavity explosion, resulting in a difference between the actual number of welding layers in the negative electrode tab area and the designed number of layers in the negative electrode tab area. This may lead to an increase in interface contact resistance, a decrease in the bonding strength between the negative electrode tab area and the electrode sheet, and further lead to the detachment or loose connection of the negative electrode tab area, or a significant local temperature rise in the prismatic battery, which may trigger a thermal runaway chain reaction. Therefore, controlling W1 / W2 within the range of 2.5-7.5 improves the safety performance of prismatic batteries while reducing wrinkles and folds in the negative electrode tab area.
[0106] Table 2 shows some characteristics and performance of the negative electrode sheets in Examples 2, 5-6 and Comparative Examples 3-4.
[0107]
[0108] Please refer to Table 2. Comparing Examples 2, 5-6, and Comparative Examples 3-4, it can be seen that when the ratio of the width of the negative electrode tab region to the preset spacing between the reinforcing layer and the negative electrode active material layer is greater than 400, i.e., the preset spacing is small, the reinforcing layer and the negative electrode active material layer fuse, which may lead to abnormal interface contact and stress concentration, and also reduce the utilization rate of the active material. As the preset spacing increases, i.e., the W1 / G ratio decreases, the fusion of the reinforcing layer and the negative electrode active material layer can be avoided. Furthermore, as the W1 / G ratio decreases, the negative electrode tab deviation value is relatively stable. However, when the W1 / G ratio is less than 22, the negative electrode tab deviation value is large. This is because the spacing between the reinforcing layer and the negative electrode active material layer is too large, failing to utilize the reinforcing layer's function, leading to increased wrinkling. Therefore, controlling the W1 / G ratio reduces mutual solubility and simultaneously reduces negative electrode tab wrinkling and folding, improving the safety performance of the prismatic battery.
[0109] Table 3, Partial Characteristics and Performance of the Negative Electrode Sheets in Examples 2 and 7-11
[0110]
[0111] Please refer to Table 3. Comparing Examples 2 and 7-8, it can be seen that when the thickness of the negative electrode current collector is consistent, as the ratio of the reinforcing layer thickness to the negative electrode current collector thickness increases, the negative electrode tab deviation and the proportion of negative electrode tab folds decrease. This indicates that increasing the thickness of the reinforcing layer can reduce negative electrode tab wrinkles and folds. Furthermore, as the ratio increases, the negative electrode tab deviation and the proportion of negative electrode tab folds tend to stabilize. To control costs, the ratio of the reinforcing layer thickness to the negative electrode current collector thickness is controlled between 1 and 6. Comparing Examples 2 and 9-11, it can be seen that when the ratio of the reinforcing layer thickness to the negative electrode current collector thickness is consistent, as the thickness of the negative electrode current collector decreases, the negative electrode tab deviation and the proportion of negative electrode tab folds increase, but remain within a small range overall. This indicates that as the thickness of the negative electrode current collector decreases, the number of negative electrode tab wrinkles and folds increases. Setting a reinforcing layer can improve the wrinkling and folding of the negative electrode tabs. Therefore, as the thickness of the negative electrode current collector decreases, the ratio of the thickness of the reinforcing layer to the thickness of the negative electrode current collector can be increased to improve the wrinkling and folding of the negative electrode tab.
[0112] In summary, the prismatic battery and electronic device provided by this utility model, by setting a reinforcing layer, can provide better support when the width of the negative electrode tab area is large, avoiding wrinkles, folds, and insertion of the negative electrode tab. It also prevents the reinforcing layer from being too wide and encroaching on the welding area of the negative electrode tab, ensuring the size of the welding area and improving the safety performance of the prismatic battery. By controlling the preset spacing, it can prevent the reinforcing layer and the negative electrode active material layer from fusing together, thus avoiding bulging and ensuring the welding area of the negative electrode tab, reducing wrinkles and folds of the negative electrode tab, improving the performance of the prismatic battery, and reducing safety hazards. It is suitable for thinner negative electrode current collectors, reducing wrinkling of the negative electrode current collector in cases of thinner negative electrode current collectors or multi-layered negative electrode tabs. By controlling the composition of the reinforcing layer, the negative electrode production line can eliminate the need for organic gas recovery equipment, simplifying the manufacturing process. Controlling the grayscale value of the reinforcing layer reduces laser reflection during laser cutting; for the same cutting thickness, lower laser power can be used, reducing laser energy consumption during die-cutting, minimizing foil leakage, and improving the energy density and cycle performance of the prismatic battery. It also improves the adhesion between the reinforcing layer and the negative electrode current collector, reducing reinforcing layer peeling. Adding reinforcing ribs increases the strength of the reinforcing layer, reduces negative electrode tab wrinkles, and further increases the width of the negative electrode tab area, allowing for more layers of negative electrode tabs and reducing the DC impedance of the prismatic battery.
[0113] The above description is only a preferred embodiment of this application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in this application is not limited to the technical solutions formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the concept of the utility model. For example, technical solutions formed by replacing the above features with technical features with similar functions disclosed in this application (but not limited to) each other.
[0114] Apart from the technical features described in the specification, the other technical features are known to those skilled in the art. To highlight the innovative features of this utility model, the other technical features will not be described in detail here.
Claims
1. A prismatic battery, characterized in that, include: The housing includes an opening. An electrode assembly disposed within the housing and a cover plate assembly sealing the opening; The electrode assembly includes a positive electrode, a diaphragm, and a negative electrode. Along a predetermined direction, the electrode assembly includes at least a main body and a negative electrode tab. The negative electrode tab includes a bent portion and a connecting portion. The connecting portion is fixedly connected to the cover plate assembly, and the bent portion is connected between the main body and the connecting portion. The negative electrode sheet includes a negative current collector, the negative current collector includes a negative electrode tab region and a negative electrode active region located on at least one side of the negative electrode current collector, and a negative electrode active material layer is coated on the negative electrode active region; along a predetermined direction, a reinforcing layer is coated on at least one side of at least a portion of the negative electrode tab region, the width of the negative electrode tab region is W1 mm, the width of the reinforcing layer is W2 mm, and the condition 2.5≤W1 / W2≤7.5 is met; The reinforcing layer covers at least a portion of the bent portion.
2. The prismatic battery according to claim 1, characterized in that, Along the preset direction, there is a preset distance G mm between the negative electrode active material layer and the reinforcing layer, satisfying 22≤W1 / G≤400.
3. The prismatic battery according to claim 2, characterized in that, The preset spacing is 0.1mm-1.1mm.
4. The prismatic battery according to claim 1, characterized in that, Along the preset direction, the width of the negative electrode active material layer is W3 mm, satisfying 3≤W3 / W1≤11.
5. The prismatic battery according to claim 1, characterized in that, The ratio of the thickness of the reinforcing layer on one side to the thickness of the negative electrode current collector is 1-6; or, The thickness of the negative electrode current collector is 4μm-5.5μm.
6. The prismatic battery according to claim 1, characterized in that, The grayscale value of the reinforcing layer is 0-110.
7. The prismatic battery according to claim 1, characterized in that, A portion of the negative electrode active material layer covers at least a portion of the surface of the negative electrode tab along the preset direction; or, a transition region is provided between the negative electrode tab and the negative electrode active material layer coating area, and the reinforcing layer is located on a portion of the transition region and a portion of the surface of the negative electrode tab.
8. The prismatic battery according to claim 7, characterized in that, The negative electrode tab also includes multiple reinforcing ribs, and the reinforcing ribs are stamped and formed by the negative electrode tab. The reinforcing ribs are arranged in at least one of the following shapes: dotted, strip-shaped, wavy, or zigzag. The ratio of the width of the maximum overlap position of the reinforcing ribs and the reinforcing layer to the width of the reinforcing layer is 0.1-1.
9. The prismatic battery according to claim 1, characterized in that, The electrode assembly is covered with a first adhesive tape, which is disposed on the side of the negative electrode tab facing away from the cover plate assembly. The first adhesive tape includes a first adhesive area, a second adhesive area, and a non-adhesive area located between the first adhesive area and the second adhesive area. The first adhesive area covers the main body, and the second adhesive area covers the connecting portion. In the thickness direction of the electrode assembly, the orthogonal projection of the reinforcing layer is completely located within the non-adhesive area.
10. An electronic device, characterized in that, Includes the prismatic battery as described in any one of claims 1-9.