Battery, electronic device and polarity leading-out method
By setting and cleaning the welding area on the inner surface of the battery shell, reducing the impurity content and designing the welding trajectory, the problem of explosive points in the battery shell welding is solved, and the safety performance and current carrying capacity of the battery are improved.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-12
- Publication Date
- 2026-03-12
AI Technical Summary
Traditional battery shells are prone to explosion points during welding, causing electrolyte leakage and affecting battery safety performance.
A first welding area is set on the inner surface of the shell, and the impurity content is reduced by laser cleaning or other means to ensure that the ion count ratio of the negative ion organic peak is ≤0.5%. The welding trajectory is designed to increase the flow area. The second welding area is treated in the same way when welding the collecting plate to the shell.
It effectively reduces the formation of explosion points during welding, improves battery safety, reduces the risk of leakage, enhances the battery's current carrying capacity, and meets high-rate charge and discharge requirements.
Smart Images
Figure CN2024105251_12032026_PF_FP_ABST
Abstract
Description
Battery, electronic device and polarity leading method
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This application claims priority to the Chinese patent application No. 202310847718.3 filed on July 12, 2023 and entitled "Battery, electronic device and polarity leading method", the content of which is incorporated herein by reference in its entirety TECHNICAL FIELD
[0003] Embodiments of the present application relate to the field of electrochemistry, in particular to a battery, an electronic device and a polarity leading method. BACKGROUND
[0004] The conventional battery usually adopts a shell directly leading out a negative electrode. The shell and a bare cell in the battery are welded to realize the conduction of the shell and the bare cell. However, since the surface of the shell may have impurities with low melting point and low boiling point, these impurities are easily gasified during the welding process, and the gas formed by the gasification is easy to diffuse to the outside through the welding position, so that a burst point is formed at the welding position. Moreover, the burst point will cause the electrolyte in the shell to flow out of the shell, affecting the safety performance of the battery.
[0005] SUMMARY
[0006] Embodiments of the present application aim to provide a battery, an electronic device and a polarity leading method to improve the problem that the shell welding is easy to form a burst point.
[0007] In order to solve the technical problems, the embodiments of the present application adopt the following technical solutions:
[0008] In a first aspect, the present application provides a battery, comprising a shell and an electrode assembly received in the shell, an inner surface of the shell is provided with a first welding area, the first welding area is used for electrically connecting with the electrode assembly, the first welding area comprises a negative ion organic peak 118, an ion count ratio of the negative ion organic peak 118 is A1%, and A1≤0.5. The welding area is an area enclosed by a welding track.
[0009] In the above technical solution, the shell can be welded with the electrode assembly through the first welding area to lead out the positive electrode or the negative electrode of the electrode assembly. The degree of impurities contained in the first welding area can be defined by the content of the rust inhibitor component. When the first welding area is cleaned on the shell, the main component after thermal cracking of the rust inhibitor is triethanolamine, and the corresponding organic peak is 118. Since the ion count ratio of the negative ion organic peak 118 of the first welding area is A1%, A1≤0.5, the content of impurities contained therein is significantly reduced, which can effectively reduce the formation of burst points when welding the shell and the electrode assembly, thereby reducing the risk of liquid leakage of the battery and improving the safety performance of the battery.
[0010] In some preferred embodiments, the battery further comprises a current collector electrically connected between the shell and the electrode assembly. A surface of the current collector facing the first welding area is provided with a second welding area, and the second welding area is welded to the first welding area. The second welding area comprises negative ion organic peaks 118, and the ion count ratio of the negative ion organic peaks 118 of the second welding area is A2%, A2≤0.5.
[0011] In the above technical solution, the current collector is electrically connected between the shell and the electrode assembly, which can increase the overcurrent area and improve the current carrying capacity of the battery, thereby meeting the large rate charge and discharge requirements of the battery. Moreover, the ion count ratio of the negative ion organic peaks 118 of the first welding area and the second welding area is ≤0.5%, which can effectively reduce impurities in the first welding area and the second welding area. When the shell and the current collector are welded, the formation of burst points can be further reduced, thereby reducing the risk of liquid leakage of the battery and further improving the safety performance of the battery.
[0012] In some preferred embodiments, A1≤0.1, which can further reduce impurities in the first area, thereby reducing the formation of burst points when the shell and the current collector are welded, and improving the safety performance of the battery.
[0013] In some preferred embodiments, A2≤0.1, which can further reduce impurities in the second area, thereby reducing the formation of burst points when the shell and the current collector are welded, and improving the safety performance of the battery.
[0014] In some preferred embodiments, the inner surface of the bottom of the shell is provided with a first area, and the projection of the first welding area at least partially locates within the projection of the first area when viewed in the first direction. The first direction is from the bottom of the shell to the electrode assembly. The first welding area can be directly welded to the electrode assembly or the current collector, the first area is a laser cleaning area, and the ion count ratio of the negative ion organic peaks 118 of the first area is ≤0.5%. The first welding area at least partially locates within the first area, which can reduce impurities in this part, thereby reducing the formation of burst points when the shell is welded.
[0015] In some preferred embodiments, the projection of the first welding area is entirely located within the projection of the first area. The first welding area is part of the first area, and impurities at all positions of the first welding area can be reduced, thereby further reducing the formation of burst points when the shell is welded.
[0016] In some preferred embodiments, the surface of the current collector facing the bottom of the shell is provided with a second area, and the projection of the second welding area at least partially locates within the projection of the second area when viewed in the first direction. The first welding area at least partially locates within the first area, which can reduce impurities in this part, thereby reducing the formation of burst points when the shell and the current collector are welded.
[0017] In some preferred embodiments, the projection of the second welding area is entirely within the projection of the second region when viewed in the first direction, thereby further reducing the formation of blowholes when the shell and the current collector are welded.
[0018] In some preferred embodiments, the bottom of the shell comprises a first portion and a second portion, the first region is disposed on the first portion, and the projection of the second portion does not overlap the projection of the first portion when viewed in the first direction; the thickness of the first portion is T1 and the thickness of the second portion is T2 in the first direction, and 6 μm≤T1-T2≤20 μm. The thickness of the shell does not decrease after cleaning, but slightly increases, so that the strength of the shell can be further improved, and the probability of the shell being welded through when welding is reduced.
[0019] Optionally, the current collector comprises a third portion and a fourth portion, the second region is disposed on the third portion, and the projection of the third portion does not overlap the projection of the fourth portion when viewed in the first direction; the thickness of the third portion is T3 and the thickness of the fourth portion is T4 in the first direction, and 6 μm≤T3-T4≤20 μm. The thickness of the current collector does not decrease after cleaning, but slightly increases, so that the strength of the current collector can be further improved to facilitate welding with the shell.
[0020] In some preferred embodiments, 10 μm≤T1-T2≤18 μm, the thickness of the shell increases after cleaning, so that the strength of the shell can be further improved, and the probability of the shell being welded through when welding is further reduced.
[0021] In some preferred embodiments, 10 μm≤T3-T4≤18 μm, the strength of the current collector can be further improved to facilitate welding with the shell.
[0022] In some preferred embodiments, the concentric distance between the first region and the shell is C1, and C1≤0.5 mm; and / or, the concentric distance between the second region and the current collector is C2, and C2≤0.5 mm. The cleaning region is preferably located at the center of the shell or the current collector to facilitate direct welding on the first region and the second region when welding.
[0023] In some preferred embodiments, the first welding area has a welding track, and the welding track is in a spiral shape or an arc shape. The spiral shape or the arc shape can increase the welding area, not only ensuring stable connection, but also facilitating increased flow.
[0024] In some preferred embodiments, the welding track has an inscribed circle with a diameter D, and 4 mm≤D≤6 mm, to facilitate the projection of the first welding area falling within the above-mentioned first region and second region, thereby further reducing the formation of blowholes.
[0025] In some preferred embodiments, the welding track has a track length L, and 8 mm≤L≤30 mm, to further ensure the welding area.
[0026] In some preferred embodiments, the first region is annular, the inner diameter of the annular first region is D1, 2mm≤D1≤100mm, and the outer diameter of the annular first region is D2, 5mm≤D2≤200mm; in combination with the size design of the first welding area described above, the first welding area can be conveniently located in the first region. And / or, the second region is annular, the inner diameter of the annular second region is D3, 2mm≤D3≤100mm, and the outer diameter of the annular second region is D4, 5mm≤D4≤200mm, so as to facilitate the second welding area to fall into the second region.
[0027] In some preferred embodiments, the first region is circular, and the diameter of the first region is D5, 5mm≤D5≤100mm. And / or, the second region is circular, and the diameter of the second region is D6, 5mm≤D6≤100mm.
[0028] In a second aspect, the present application further provides an electronic device comprising the battery as described in any one of the embodiments of the first aspect.
[0029] In a third aspect, the present application further provides a polarity leading method, comprising: providing a shell, laser cleaning a first welding area on the inner surface of the shell, the first welding area comprising a negative ion organic peak 118, the ion count ratio of the negative ion organic peak 118 being A1%, A1≤0.5; providing an electrode assembly, the electrode assembly being accommodated in the shell, and the electrode assembly being welded with the first welding area, the shell leading the positive electrode or the negative electrode of the electrode assembly.
[0030] In some preferred embodiments, the method further comprises: providing a current collector, the current collector being electrically connected with the electrode assembly; laser cleaning a second welding area on the current collector, the second welding area being welded and connected with the first welding area of the shell, the second welding area comprising a negative ion organic peak 118, the ion count ratio of the negative ion organic peak 118 of the second welding area being A2%, A2≤0.5.
[0031] The above description is only a summary of the technical solutions of the present application. In order to enable the technical means of the present application to be more clearly understood, and to be implemented according to the content of the description, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more apparent and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS
[0032] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are schematic and not intended to be limiting of the embodiments, and in which like reference numerals designate similar items in the figures and wherein:
[0033] Fig. 1 is an exploded view of a battery according to some embodiments of the present application;
[0034] Figure 2 is a sectional view of a battery according to some embodiments of the present application;
[0035] Figure 3 is a schematic view of a winding structure of an electrode assembly according to some embodiments of the present application;
[0036] Figure 4 is an enlarged view of a portion of Figure 2 at B according to some embodiments of the present application;
[0037] Figure 5 is a schematic view of cleaning of a first region at a bottom of a case according to some embodiments of the present application;
[0038] Figure 6 is a schematic view of a structure of a bottom of a case according to some embodiments of the present application;
[0039] Figure 7 is a schematic view of a structure of a wire bonding trace according to some embodiments of the present application;
[0040] Figure 8 is a schematic view of cleaning of a first region at a bottom of a case according to some embodiments of the present application;
[0041] Figure 9 is a schematic view of cleaning of a first region at a bottom of a case according to some embodiments of the present application;
[0042] Figure 10 is a thermal cracking analysis diagram of a rust preventive according to some embodiments of the present application;
[0043] Figure 11 is a schematic view of a bottom of a case before and after laser cleaning according to some embodiments of the present application;
[0044] Figure 12 is a schematic view of a bottom of a case after laser cleaning according to some embodiments of the present application.
[0045] BRIEF DESCRIPTION OF THE DRAWINGS
[0046] 100, battery;
[0047] 10, case; 11, accommodation cavity; 12, first opening; 13, bottom of the case; 131, first region; 132, first bonding area; 1322, bonding trace; 133, first portion; 134, second portion;
[0048] 20, electrode assembly; 21, first electrode tab; 22, second electrode tab; 23, separator;
[0049] 30, current collector; 31, second region; 32, second bonding area; 33, third portion; 34, fourth portion;
[0050] 40, cover plate; 41, electrode post;
[0051] 50, top current collecting member;
[0052] Z, first direction. DETAILED DESCRIPTION
[0053] The technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.
[0054] It should be noted that when an element is described as "fixed to", "arranged on" another element, it can be directly on the other element, or one or more intermediate elements can be present therebetween. When an element is described as "connected to" or "welded to" another element, it can be directly connected / welded to the other element, or one or more intermediate elements can be present therebetween.
[0055] In the description of the embodiments of the present application, the technical terms "upper", "lower", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.
[0056] In the description of the embodiments of the present application, the technical terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.
[0057] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents a "or" relationship between the front and rear associated objects.
[0058] Reference to "embodiments" in this document means that the specific features, structures or properties described in conjunction with the embodiments can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily all refer to the same embodiments, nor is it necessarily every embodiment mutually exclusive or alternative to other embodiments. In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.
[0059] In a first aspect, the present application proposes a battery 100, please refer to figure 1, the battery 100 includes a shell 10, an electrode assembly 20 and a current collector 30, the electrode assembly 20 is contained in the shell 10, and the current collector 30 is electrically connected between the shell 10 and the electrode assembly 20.
[0060] Referring to FIGS. 1 and 2, the shell 10 encloses a receiving cavity 11, which can accommodate the electrode assembly 20 and electrolyte (not shown). For example, the top of the shell 10 is provided with a first opening 12, and the electrode assembly 20 can be disposed in the shell 10 through the first opening 12. The first opening 12 is covered by a cover plate 40 to seal the receiving cavity 11. The cover plate 40 can be provided with a pole 41, and the electrode assembly 20 is electrically connected to the pole 41, for example, through a top current collector 50. The pole 41 extends out of the receiving cavity 11 to lead out the positive or negative electrode of the electrode assembly 20.
[0061] In some embodiments, the shell 10 can be punched and formed from a metal sheet. The thickness of the metal sheet can be 0.1 mm to 0.4 mm, so that the shell 10 has better punching strength and improves the energy density of the battery 100. The metal sheet can be made of conductive metal materials such as aluminum, steel, stainless steel, nickel, copper, or magnesium alloy. In this way, the shell 10 can lead out a certain polarity of the battery 100, for example, the shell 10 itself as the positive or negative electrode of the battery 100. Specifically, the pole 41 can lead out the positive electrode of the electrode assembly 20, and the negative electrode of the electrode assembly 20 can be directly electrically connected to the shell 10, which leads out the negative electrode of the electrode assembly 20. Alternatively, the pole 41 leads out the negative electrode, and the shell 10 leads out the positive electrode.
[0062] Referring to FIGS. 2 and 3, the electrode assembly 20 is a wound electrode assembly 20. The electrode assembly 20 includes a first electrode sheet 21, a second electrode sheet 22, and a separator 23. The first electrode sheet 21, the second electrode sheet 22, and the separator 23 are stacked and wound to form the wound electrode assembly 20. The first electrode sheet 21 and the second electrode sheet 22 have opposite polarities. For example, the first electrode sheet 21 is a positive electrode sheet, and the second electrode sheet 22 is a negative electrode sheet. The separator 23 is disposed between the first electrode sheet 21 and the second electrode sheet 22 to separate them. In other embodiments, the first electrode sheet 21 can be a negative electrode sheet, and the second electrode sheet 22 can be a positive electrode sheet.
[0063] For the isolation film 23, please refer to FIG. 3. The isolation film 23 is arranged between the first tab 21 and the second tab 22 to separate the first tab 21 and the second tab 22. The isolation film 23 can be a high-adhesion isolation film 23, i.e., the isolation film 23 is bonded between the first tab 21 and the second tab 22, so as to improve the bonding strength of the electrode assembly 20 as a whole, thereby reducing the risk of battery 100 drop or collision failure. Alternatively, in some other embodiments, a first adhesive layer (not shown in the figure) is arranged on the surface of the isolation film 23 facing the first tab 21, and the first adhesive layer is bonded between the isolation film 23 and the first tab 21; a second adhesive layer (not shown in the figure) is arranged on the surface of the isolation film 23 facing the second tab 22, and the second adhesive layer is bonded between the isolation film 23 and the second tab 22. The isolation film 23 can be one or more of a polyethylene isolation film, a polyethylene coated isolation film containing ceramic, a polyethylene coated isolation film containing an adhesive coating, a polypropylene isolation film, and a polypropylene coated isolation film.
[0064] For the current collector 30, please refer to FIG. 1 and FIG. 2. The current collector 30 is electrically connected to the electrode assembly 20 in the housing 10, for example, the current collector 30 is arranged at the bottom of the accommodation cavity 11 and is electrically connected between the housing 10 and the electrode assembly 20. The electrode assembly 20 further includes a first tab (not shown in the figure) and a second tab (not shown in the figure) with opposite polarities, the first tab is electrically connected to the first tab 21, and the second tab is electrically connected to the second tab 22. After the above-mentioned tabs and isolation film 23 are wound to form the electrode assembly 20, the first tab can extend from the upper end of the electrode assembly 20, and the second tab can extend from the lower end. The second tab at the lower end can be flattened to form a flattened surface at the lower end of the electrode assembly 20, and the current collector 30 can be directly welded between the flattened surface and the bottom 13 of the housing; similarly, the first tab at the upper end can also be flattened to form another flattened surface at the upper end of the electrode assembly 20, and the top current collecting part 50 can be directly welded between the upper end flattened surface and the cover plate 40.
[0065] For the electrical connection between the housing 10 and the electrode assembly 20, the housing 10 can be electrically connected to the second tab, the flattened surface formed by the second tab, or the current collector 30 by welding. It can be understood that when the battery 100 does not use the current collector 30, the housing 10 can be directly welded with the second tab or the flattened surface formed by the second tab to lead out one polarity of the battery 100. In the embodiments of the present application, the current collector 30 can be used, and the current collector 30 is electrically connected between the housing 10 and the electrode assembly 20. The current collector 30 can be first electrically connected to the electrode assembly 20, and the electrical connection includes but is not limited to welding or conductive adhesive connection, and then the current collector 30 is welded with the housing 10. The arrangement of the current collector 30 can increase the overcurrent area and improve the current carrying capacity of the battery 100, so as to meet the large rate charge and discharge requirements of the battery 100.
[0066] When the shell 10 is directly welded with the second lug of the electrode assembly 20 or the second lug formed flat surface, for example, the shell 10 is provided with a first welding area 132 (see FIG. 4), high energy is applied to the outer surface of the shell 10, and a molten pool is formed on the surface of the shell 10 by high energy output, the molten pool penetrates through the shell 10 and acts on the second lug or the flat surface formed by the second lug, so that the second lug or the flat surface formed by the second lug also forms a molten pool, and then the molten pool is rapidly solidified, so that the shell 10 is welded and fixed with the second lug or the flat surface formed by the second lug. Wherein the molten pool is formed on the inner surface of the shell 10, that is, the first welding area 132 is directly welded with the electrode assembly 20.
[0067] When the current collecting plate 30 is welded with the shell 10, for example, the current collecting plate 30 is provided with a second welding area 32 (see FIG. 4), high energy is applied to the outer surface of the shell 10, and a molten pool is formed on the surface of the shell 10 by high energy output, the molten pool penetrates through the shell 10 and acts on the current collecting plate 30, so that the surface of the current collecting plate 30 also forms a molten pool; then the molten pool is rapidly solidified, so that the shell 10 and the current collecting plate 30 are connected together to form one pole of the battery 100. Wherein the molten pool is formed on the outer surface of the current collecting plate 30, that is, the second welding area 32.
[0068] Referring to FIGS. 2 and 4, the inner surface of the bottom 13 of the shell is provided with a first region 131, which includes a negative ion organic peak 118 in a secondary ion mass spectrometry test, and the ion count ratio of the negative ion organic peak 118 is A1%, A1≤0.5. For example, the first region 131 is provided on the inner surface of the bottom 13 of the shell by laser cleaning, mechanical scraping, or chemical cleaning, and so on. For example, the first region 131 is provided on the bottom 13 of the shell by laser cleaning, and the impurities on the surface of the first region 131 can be removed by laser cleaning. The degree of cleaning can be defined by the content of the rust inhibitor on the surface of the shell 10. The rust inhibitor contains triethanolamine, and the main component after thermal cracking is triethanolamine. For example, the triethanolamine is rapidly volatilized or rapidly gasified under the action of high temperature by laser cleaning, so that the content of triethanolamine is reduced. In a secondary ion mass spectrometry test (a display mode of a substance in a spectrum, and the peak value can be used to judge which substance the peak value is), the amount of triethanolamine can roughly reflect the content of impurities. If the degree of cleaning is insufficient, the higher the content of triethanolamine, the more impurities. The organic peak 118 corresponding to triethanolamine is 118, and a better cleaning effect can be achieved by controlling the content of the organic peak 118 to be less than or equal to 0.5%. Referring to FIG. 10, it can be seen from FIG. 10 that the organic peak 118 corresponding to triethanolamine is fragmented after thermal cracking. It can be understood that the formation of the first region 131 is not limited to the above-mentioned laser cleaning, mechanical scraping, or chemical cleaning, and so on. The first region 131 can reduce some impurities on the surface of the first region 131, so that the first region 131 meets the requirement that the ion count ratio of the negative ion organic peak 118 is less than or equal to 0.5%.
[0069] Referring to FIGS. 2 and 4, the bottom 13 of the shell is further provided with a first welding region 132, which is a region enclosed by a welding track, and the first welding region 132 is configured to be welded with the current collector plate 30 or the electrode assembly 20. For example, high energy is applied to the first welding region 132 of the shell 10, and a molten pool is formed in the first welding region 132 to fix the shell 10 directly with the electrode assembly 20 or the current collector plate 30.
[0070] Viewed in the direction (the first direction Z) from the bottom 13 of the shell to the electrode assembly 20, the projection of the first welding region 132 is at least partially located within the projection of the first region 131. The first region 131 formed by the above-mentioned laser cleaning, mechanical scraping, or chemical cleaning, and so on has a significantly reduced surface impurity, and since the first welding region 132 falls within the first region 131, that is, the first welding region 132 includes the negative ion organic peak 118, and the ion count ratio of the negative ion organic peak 118 is A1%, A1≤0.5. When the shell 10 is welded, the explosion point can be effectively reduced to ensure the safety performance of the battery 100.
[0071] In some embodiments, the projection of the first welding area 132 is entirely within the projection of the first region 131. The first welding area 132 is a part of the first region 131, and the impurities at all positions of the first welding area 132 can be reduced, thereby further reducing the formation of burst points when the shell 10 is welded.
[0072] Preferably, when the current collector plate 30 is used, the surface of the current collector plate 30 facing the bottom 13 of the shell is provided with a second region 31, and the second region 31 includes negative ion organic peaks 118, and the ion count ratio of the negative ion organic peaks 118 is A2%, A2≤0.5%. The second region 31 can also be formed on the current collector plate 30 by means of laser cleaning, mechanical scraping, or chemical cleaning, etc. By laser cleaning, impurities on the surface of the second region 31 can be removed. When viewed in the first direction Z, the projection of the first region 131 at least partially overlaps the projection of the second region 31, so that the welding area is located in the part where the projections of the first region 131 and the second region 31 overlap. The ion count ratio of the negative ion organic peaks 118 of the first region 131 and the second region 31 is ≤0.5%, which can effectively reduce the impurities of the first region 131 and the second region 31.
[0073] The surface of the current collector plate 30 facing the shell 10 is provided with a second welding area 32, and the second welding area 32 is an area enclosed by a welding track, and the second welding area 32 is welded to the first welding area 132. When viewed in the first direction Z, the projection of the second welding area 32 is at least partially within the projection of the second region 31, and the second welding area 32 falls within the first region 131, that is, the second welding area 32 includes negative ion organic peaks 118, and the ion count ratio of the negative ion organic peaks 118 is A2%, A2%≤0.5%. This can effectively reduce the impurities of the first welding area 132 and the second welding area 32. When the shell 10 and the current collector plate 30 are welded, the formation of burst points can be further reduced, thereby reducing the risk of liquid leakage of the battery 100, and further improving the safety performance of the battery 100.
[0074] In some embodiments, when viewed in the first direction Z, the projection of the second welding area 32 is entirely within the projection of the second region 31. The second welding area 32 is a part of the second region 31, and the impurities at all positions of the second welding area 32 can be reduced, thereby further reducing the formation of burst points when the shell 10 is welded.
[0075] The area where the projections of the first welding area 132 and the second welding area 32 overlap, whether for the shell 10 or the current collector plate 30, the impurities at the welding position are significantly reduced, and when the shell 10 and the current collector plate 30 are welded, the formation of burst points can be further reduced, thereby reducing the risk of liquid leakage of the battery 100, and further improving the safety performance of the battery 100.
[0076] Further, A1≤0.1, by cleaning the ion count ratio of the negative ion organic peak 118 to less than 0.1%, the impurities in the first region 131 can be further reduced, thereby reducing the formation of explosion points when the shell 10 is welded with the electrode assembly 20 or the current collector plate 30, and improving the safety performance of the battery 100. Further, A2≤0.1, the impurities in the second region 31 can be further reduced, thereby improving the safety performance of the battery 100.
[0077] Referring again to FIGS. 2 and 4, the bottom 13 of the shell includes a first portion 133 and a second portion 134 (the first portion 133 and the second portion 134 are separated by a straight line M in FIG. 4), the first region 131 is provided in the first portion 133, and the projection of the second portion 134 does not overlap the projection of the first portion 133 when viewed in the first direction Z. For example, the first portion 133 is located at the middle of the bottom 13 of the shell, and the second portion 134 is provided around the first portion 133. The first portion 133 is subjected to laser cleaning so that the first region 131 is formed in the first portion 133, thereby reducing the surface impurities of the first region 131.
[0078] For the thickness (thickness in the first direction Z) of the first portion 133 and the second portion 134, the difference in thickness of the two portions can change after laser cleaning. In the first direction Z, the thickness of the first portion 133 is T1, and the thickness of the second portion 134 is T2, 6 μm≤T1-T2≤20 μm. After laser cleaning, the thickness of the shell 10 does not decrease, but slightly increases. Laser cleaning is performed by applying a high-energy laser beam to the surface of a substance. Substances with low boiling points are rapidly vaporized and removed, and the material itself undergoes a melting and solidification process. When solidified, the substance will accumulate, causing a slight increase in thickness. Preferably, 10 μm≤T1-T2≤18 μm, which is advantageous for reducing the weld-through rate of the bottom 13 of the shell during welding.
[0079] Similarly, when the current collector plate 30 is used, the current collector plate 30 includes a third portion 33 and a fourth portion 34 (the third portion 33 and the fourth portion 34 are separated by a straight line N in FIG. 4), the second region 31 is located in the third portion 33, and the projection of the third portion 33 does not overlap the projection of the fourth portion 34 when viewed in the first direction Z. The fourth portion 34 can also be provided around the third portion 33. In the first direction Z, the thickness of the third portion 33 is T3, and the thickness of the fourth portion 34 is T4, 6 μm≤T3-T4≤20 μm. After cleaning, the thickness of the current collector plate 30 does not decrease, but slightly increases, to facilitate welding with the shell 10. Preferably, 10 μm≤T3-T4≤18 μm.
[0080] The laser cleaning mainly includes cleaning of the shell 10 and cleaning of the current collecting plate 30. The cleaning of the shell 10 is to clean the inner surface of the bottom 13 of the shell, which is the surface adhering to the current collecting plate 30. The dirt on the adhering surface causes the formation of a penetrating burst point. Referring to FIG. 5, the cleaning needs to meet the following conditions: the cleaning area (the first area 131) has a concentric distance C1 from the bottom 13 of the shell, and C1≤0.5 mm; and / or when the current collecting plate 30 is used, the second area 31 has a concentric distance C2 (not shown in the figure) from the current collecting plate 30, and C2≤0.5 mm. The cleaning area is preferably located at the center of the bottom 13 of the shell or the current collecting plate 30, so that the first welding area 132 and the second welding area 32 fall into the first area 131 and the second area 31 during welding.
[0081] Referring to FIG. 6, the first welding area 132 has a concentric distance C3 from the bottom 13 of the shell, and C3≤0.9 mm, so that the first welding area 132 can be welded to the first area 131 and the second area 31 at the same time. Referring to FIG. 7, the first welding area 132 has a welding track 1322, and the first welding area 132 is an area enclosed by the welding track. The welding track 1322 is in a spiral shape or an arc shape. The spiral shape or the arc shape can increase the welding area, which not only ensures stable connection, but also facilitates the increase of the flow. Optionally, the track length of the welding track 1322 is L (not shown in the figure), and 8 mm≤L≤30 mm, so as to further ensure the welding area.
[0082] Optionally, the diameter of the circumscribed circle of the welding track 1322 is D, and 4 mm≤D≤6 mm, so as to facilitate the first welding area 132 to fall into the first area 131 and the second area 31, thereby reducing the formation of burst points.
[0083] In some embodiments, referring to FIG. 8, the first area 131 is in a ring shape, the inner diameter of the ring-shaped first area 131 is D1, and 2 mm≤D1≤100 mm. The outer diameter of the ring-shaped first area 131 is D2, and 5 mm≤D2≤200 mm. In combination with the size design of the first welding area 132, the first welding area 132 can fall into the first area 131.
[0084] Optionally, when the current collecting plate 30 is used, the second area 31 is in a ring shape, the inner diameter of the ring-shaped second area 31 is D3 (not shown in the figure), and 2 mm≤D3≤100 mm. The outer diameter of the ring-shaped second area 31 is D4, and 5 mm≤D4≤200 mm, so as to facilitate the first welding area 132 to fall into the second area 31.
[0085] In some other embodiments, referring to FIG. 9, the first area 131 is circular, and the diameter of the first area 131 is D5, 5mm≤D5≤7mm. Optionally, when the current collector plate 30 is used, the second area 31 is circular, and the diameter of the second area 31 is D6, 5mm≤D6≤7mm. The shapes of the first area 131 and the second area 31 are various, and the application does not limit them.
[0086] In the embodiments of the application, the shell 10 can be welded with the electrode assembly 20 through the first welding area 132 to lead out the positive or negative electrode of the electrode assembly 20. The degree of impurities contained in the first welding area 132 can be defined by the content of the rust inhibitor component. When the first welding area 132 is cleaned on the shell 10, the main component after the thermal cracking of the rust inhibitor is triethanolamine, and the corresponding organic peak is 118. Since the ion count ratio of the negative ion organic peak 118 of the first welding area 132 is A1%, A1≤0.5, the content of impurities is obviously reduced. When the shell 10 is welded with the electrode assembly 20, the formation of the burst point of the shell 10 can be effectively reduced, thereby reducing the risk of liquid leakage of the battery 100 and improving the safety performance of the battery 100.
[0087] In the embodiments of the application, taking a steel shell battery as an example, the bottom of the shell is subjected to time-of-flight secondary ion mass spectrometry.
[0088] In Example 1, the bottom of the shell is cleaned by laser cleaning, the cleaning shape is circular arc (circular ring), and the cleaning degree is that the surface of the shell is whitened.
[0089] In Example 2, the bottom of the shell is cleaned by laser cleaning, the cleaning shape is circular arc (circular ring), and the cleaning degree is that the surface of the shell is melted.
[0090] In Example 3, the bottom of the shell is cleaned by laser cleaning, the cleaning shape is circular arc (circular ring), and the cleaning degree is whitening.
[0091] In Example 4, the bottom of the shell is cleaned by laser cleaning, the cleaning shape is circular arc (circular ring), and the cleaning degree is that the surface of the shell is melted.
[0092] In Example 5, the bottom of the shell is cleaned by laser cleaning, the cleaning shape is circular arc (circular ring), and the cleaning degree is that the surface of the shell is melted.
[0093] In Comparative Example 1, no cleaning is performed.
[0094] In Comparative Example 2, the bottom of the shell is cleaned by laser cleaning, the cleaning shape is circular arc (circular ring), and the cleaning degree is no trace.
[0095] The cleaning degrees of no trace, whitening, and melting can be referred to FIG. 11 and FIG. 12.
[0096] The measurement method is to use tof-sims (Time of Flight Secondary Ion Mass Spectrometry) to determine the ion mass by exciting the sample surface with primary ions, ejecting a small amount of secondary ions, and according to the time of secondary ions flying to the detector due to different masses.
[0097] Test principle: using a focused primary ion beam to perform stable bombardment on the sample, the target surface generates secondary ions, and the secondary ions separated by mass spectrometry can be collected to know the element composition and distribution of the sample surface and body. The ionized secondary particles (sputtered atoms, molecules and atomic groups, etc.) are mass spectrometry separated according to the mass-to-charge ratio. The main component corresponding to the rust inhibitor thermal cracking is triethanolamine, corresponding to the organic peak 118, and the composition of the organic peak 118 can be used to determine the cleaning effect.
[0098] Explosion point test method: the flat surface of the shell and the electrode assembly is directly penetrated by welding (welding position penetrates the cleaning area), and a complete sample battery is prepared. In the early stage, various characteristic explosion point samples are collected by artificial microscopy, and then these explosion point characteristics are written into the CCD recognition software through the deep learning of the CCD, and the explosion point is automatically recognized by the algorithm. The related data of the shell ion count ratio are shown in Table 1 as follows:
[0099] Table 1
[0100] As shown in Table 1, the laser cleaning can effectively remove the negative ion organic peak 118 substance at the bottom of the shell, and the removal effect is obvious. Compared with the uncleaned group, the laser cleaning can greatly reduce the proportion of negative ion organic peak 118, thereby reducing part of the sublimation impurities on the surface of the shell, and effectively reducing the formation of explosion points when welding the shell.
[0101] As shown in Table 1, the smaller the ion count ratio of the negative ion organic peak 118 at the bottom of the shell, the smaller the explosion point ratio. When the ion count ratio of the organic peak 118 at the bottom of the shell is less than or equal to 0.50%, the explosion point ratio can be less than 0.1%. Therefore, in this application, the ion count ratio of the negative ion organic peak 118 is A1%, and A1≤0.5. As shown in Example 2 and Example 4, when the ion count ratio of the organic peak 118 is less than or equal to 0.1%, the explosion point ratio is less than 0.042%, and therefore A1≤0.10 is further preferred in this application.
[0102] In the embodiments of the present application, the steel shell battery is taken as an example to perform time-of-flight-secondary ion mass spectrometry test on the bottom of the shell and the current collector plate.
[0103] Example 6, based on the structure of Example 2 above, laser cleaning of the current collecting plate, both cleaning shapes are circular arc (circular ring), the cleaning degree is the shell surface whitening and the current collecting plate surface whitening.
[0104] Example 7, based on the structure of Example 2 above, laser cleaning of the current collecting plate, both cleaning shapes are circular arc (circular ring), the cleaning degree is the shell surface melting and the current collecting plate surface melting.
[0105] Example 8, based on the structure of Example 2 above, laser cleaning of the current collecting plate, both cleaning shapes are circular arc (circular ring), the cleaning degree is the shell surface whitening and the current collecting plate surface whitening.
[0106] Example 9, based on the structure of Example 2 above, laser cleaning of the current collecting plate, both cleaning shapes are circular arc (circular ring), the cleaning degree is the shell surface melting and the current collecting plate surface melting.
[0107] Example 10, based on the structure of Example 2 above, laser cleaning of the current collecting plate, both cleaning shapes are circular arc (circular ring), the cleaning degree is the shell surface melting and the current collecting plate surface melting.
[0108] Example 11, based on the structure of Example 2 above, no cleaning of the current collecting plate.
[0109] Example 12, based on the structure of Example 2 above, laser cleaning of the current collecting plate, cleaning shape is circular arc (circular ring), cleaning degree is no trace.
[0110] After laser cleaning of the shell and the current collecting plate, the cleaning position of each can be tested by secondary ion mass spectrometry, and the average ion count ratio of each is obtained; or, after welding of the shell and the current collecting plate, the cleaning area (non-welding point or welding line) is tested, and the ion count ratio of the shell or the current collecting plate is directly obtained. In this application, the average of both is used as an example, and the relevant data is shown in Table 2 below:
[0111] Table 2
[0112] In combination with the above Table 1 and Table 2, it can be seen that when laser cleaning is performed on the bottom of the shell and the current collecting plate at the same time, the proportion of burst points can be further reduced. The surface of the bottom of the shell facing the current collecting plate is laser cleaned to form a first area, and the surface of the current collecting plate facing the shell is laser cleaned to form a second area. The current collecting plate is attached to the bottom of the shell, and at this time the first area and the second area also at least partially overlap. During welding, the welding position is in the overlapping part of the first area and the second area, for example, penetration welding is used, and high energy output is used to form a molten pool in this part, and the molten pool penetrates the shell and the current collecting plate; after the molten pool solidifies, the shell and the current collecting plate are fixedly welded. Since the welding position is in the overlapping part of the first area and the second area, the impurities and easily vaporized substances of both the shell and the current collecting plate are significantly reduced, which can improve the cleanliness of the attachment area of the two, thereby effectively reducing the formation of burst points and reducing the risk of liquid leakage of the battery and improving the safety performance of the battery.
[0113] In combination with the above Table 1 and Table 2, it can be seen that the smaller the ion count ratio of the organic peak 118 of the shell and the current collecting plate, the smaller the proportion of burst points. When A1≤0.5 and A2≤0.5, the proportion of burst points can be further reduced; therefore, in the present application, A1≤0.5 and A2≤0.5 are taken. In combination with Example 7 and Example 9, when A1≤0.1 and A2≤0.1, the proportion of burst points can be reduced to below 0.017%, and therefore A1≤0.1 and A2≤0.1 are further preferred in the present application.
[0114] In a second aspect, the present application further provides an electronic device comprising the battery of any one of the embodiments of the first aspect. The electronic device of the present application is not particularly limited and can be any electronic device known in the prior art. For example, the electronic device includes but is not limited to a Bluetooth headset, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, and an electric plane toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, and a spacecraft, etc.
[0115] In a third aspect, the present application further provides a polarity leading-out method. One embodiment of the method includes:
[0116] S10, providing a shell, laser cleaning a first welding area on the inner surface of the shell, the first welding area comprising a negative ion organic peak 118, the ion count ratio of the negative ion organic peak 118 being A1%, and A1≤0.5.
[0117] The first welding area is a position where the shell and the electrode assembly are welded. In order to ensure that the first welding area is completely cleaned, a cleaning method of cleaning out the first area can be used. When viewed in the first direction Z, the projection of the first welding area falls completely within the projection range of the first area, that is, to ensure that the first welding area is completely cleaned.
[0118] S20, providing an electrode assembly, the electrode assembly is accommodated in the shell, and the electrode assembly is welded with the first welding area, and the shell leads out the positive electrode or the negative electrode of the electrode assembly.
[0119] The shell and the electrode assembly are welded and connected, and the positive electrode or the negative electrode of the electrode assembly can be led out. For example, the electrochemical device further includes a tab or a pole, the tab or the pole leads out the positive electrode of the electrode assembly, and the shell leads out the negative electrode. In other embodiments, the tab or the pole can also lead out the negative electrode of the electrode assembly, and the shell leads out the positive electrode.
[0120] In some embodiments, a current collector plate can also be electrically connected between the shell and the electrode assembly.
[0121] S30, providing a current collector plate, the current collector plate is electrically connected with the electrode assembly; a second welding area is cleaned out on the current collector plate by laser, the second welding area is welded with the first welding area, and the second welding area includes the negative ion organic peak 118, and the ion count ratio of the negative ion organic peak 118 of the second welding area is A2%, A2≤0.5.
[0122] By electrically connecting the current collector plate between the shell and the electrode assembly, the overcurrent area can be increased, and the current carrying capacity of the battery can be improved, so as to meet the large rate charge and discharge requirements of the battery. In addition, the ion count ratio of the negative ion organic peak 118 of the first welding area and the second welding area is ≤0.5%, which can effectively reduce the impurities of the first welding area and the second welding area. When the shell and the current collector plate are welded, the formation of the explosion point can be further reduced, thereby reducing the risk of liquid leakage of the battery, and further improving the safety performance of the battery.
[0123] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above. In order to be brief, they are not provided in details; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A battery comprising a case and an electrode assembly housed in the case, characterized by, An inner surface of the shell is provided with a first welding area for electrically connecting with the electrode assembly; In a secondary ion mass spectrometry test, the first welding area comprises negative ion organic peak 118, and an ion count ratio of the negative ion organic peak 118 is A1%, and A1≤0.
5.
2. The battery of claim 1, wherein, The battery further comprises a current collecting disc electrically connected between the shell and the electrode assembly; A surface of the current collecting disc facing the first welding area is provided with a second welding area, and the second welding area is welded with the first welding area; The second welding area comprises negative ion organic peak 118, and an ion count ratio of the negative ion organic peak 118 of the second welding area is A2%, and A2≤0.
5.
3. The battery according to claim 1 or 2, characterized in that, A1≤0.1。 4. The battery according to claim 2 or 3, characterized in that, A2≤0.1。 5. The battery of any one of claims 1 to 4, wherein, An inner surface of the bottom of the shell is provided with a first area, and a projection of the first welding area at least partially locates within a projection of the first area when viewed in a first direction; wherein the first direction is from the bottom of the shell to the electrode assembly.
6. The battery of claim 5, wherein, The projection of the first welding area entirely locates within the projection of the first area when viewed in the first direction.
7. The battery according to claim 2 or 4, characterized by A surface of the current collecting disc facing the bottom of the shell is provided with a second area, and a projection of the second welding area at least partially locates within a projection of the second area when viewed in a first direction.
8. The battery of claim 7, wherein, The projection of the second welding area entirely locates within the projection of the second area when viewed in the first direction.
9. The battery according to claim 5 or 6, characterized in that, The bottom of the shell comprises a first portion and a second portion, the first area is arranged on the first portion, and a projection of the second portion does not overlap with a projection of the first portion when viewed in the first direction; In the first direction, a thickness of the first portion is T1, a thickness of the second portion is T2, and 6 μm≤T1-T2≤20 μm.
10. The battery of claim 7 or 8, wherein, The current collecting disc comprises a third portion and a fourth portion, the second area is located on the third portion, and a projection of the third portion does not overlap with a projection of the fourth portion when viewed in the first direction; In the first direction, a thickness of the third portion is T3, a thickness of the fourth portion is T4, and 6 μm≤T3-T4≤20 μm.
11. The battery of claim 9, wherein, 10 μm≤T1-T2≤18 μm.
12. The battery of claim 10, wherein, 10 μm≤T3-T4≤18 μm.
13. The battery of any one of claims 5, 6, 9, wherein, A concentric distance of the first area from the bottom of the shell is C1, and C1≤0.5 mm.
14. The battery of any one of claims 7, 8, 10, 12, wherein, A concentric distance of the second area from the current collecting disc is C2, and C2≤0.5 mm.
15. The battery of any one of claims 1-14, wherein, The first welding area has a welding track, and the welding track is in a spiral shape or an arc shape.
16. The battery of claim 15, wherein, An inscribed circle diameter of the welding track is D, and 4 mm≤D≤6 mm.
17. The battery of any one of claims 5, 6, 9, 11, 13, wherein, The first area is in a ring shape, an inner diameter of the ring-shaped first area is D1, 2 mm≤D1≤100 mm, and an outer diameter of the ring-shaped first area is D2, 5 mm≤D2≤200 mm.
18. The battery of any one of claims 7, 8, 10, 12, 14, wherein, The second area is in a ring shape, an inner diameter of the ring-shaped second area is D3, 2 mm≤D3≤100 mm, and an outer diameter of the ring-shaped second area is D4, 5 mm≤D4≤200 mm.
19. An electronic device, comprising: The battery comprises the battery as claimed in any one of claims 1 to 18.
20. A polarity pulling method, characterized by, The battery comprises: A shell is provided, a first welding area is laser cleaned on an inner surface of the shell, the first welding area includes a negative ion organic peak 118, and an ion count ratio of the negative ion organic peak 118 is A1%, A1≤0.5; An electrode assembly is provided, the electrode assembly is accommodated in the shell, and the electrode assembly is electrically connected with the first welding area, and the shell leads out a positive electrode or a negative electrode of the electrode assembly.
21. The method of claim 20, wherein, A current collecting plate is provided, the current collecting plate is electrically connected with the electrode assembly; A second welding area is laser cleaned on the current collecting plate, the second welding area is weldedly connected with the first welding area of the shell, the second welding area includes a negative ion organic peak 118, and an ion count ratio of the negative ion organic peak 118 of the second welding area is A2%, A2≤0.5.