Battery, battery pack and electric device

Abstract

The application relates to the technical field of batteries, and discloses a battery, a battery pack and an electric device, which comprise a pole assembly arranged on a shell, a battery cell comprising a battery cell body and a tab part extending from the battery cell body, the tab part being welded with the pole assembly to form a first welding mark area; wherein the tab part contains aluminum elements, manganese elements and / or silicon elements, the mass percentage of the manganese elements and / or the silicon elements is a%, a resistance test point is formed on a non-welding area of the tab part, the first welding mark area is located between the pole assembly and the resistance test point, the resistance between the pole assembly and the resistance test point is b, the tab part comprises a plurality of tab layers arranged in a stack, the thickness of the tab layer is c, and a, b and c satisfy 0.006 <= b * a / c <= 12.5. According to the application, the overcurrent capacity between the pole assembly and the tab part is ensured, the battery voltage jump is avoided, the reliability of the battery is ensured, and the lithium precipitation risk of the battery is reduced.

Description

[0001] This application is a divisional application of the invention patent application with publication number CN2025112265942. The original application was filed on August 29, 2025; the application number was 2025112265942; and the invention was entitled "Battery, Battery Pack and Electrical Equipment". Technical Field

[0002] This invention relates to the field of battery technology, specifically to batteries, battery packs, and electrical devices. Background Technology

[0003] A battery pack, as an electrical device that houses multiple batteries, is configured in series or parallel. The consistency between the batteries determines the cycle life of the battery pack. However, during use, various operating conditions can cause voltage inconsistencies between the batteries, resulting in significant voltage differences that affect battery safety and cycle life. Summary of the Invention

[0004] In view of this, the present invention provides a battery, a battery pack, and an electrical device to solve the problem in the prior art where the battery voltage fluctuates, affecting the stability of the battery output voltage and impacting the battery's safety and cycle life.

[0005] In a first aspect, the present invention provides a battery, comprising: a casing; a terminal assembly disposed on the casing; and a battery cell disposed within the casing, the battery cell comprising a cell body and a tab extending from at least one end of the cell body, the tab being welded to the terminal assembly to form a first solder area, the tab comprising a plurality of stacked tab layers, the casing having a lead-out through hole, the terminal assembly being at least partially disposed in the lead-out through hole, and the tab being at least partially located within the lead-out through hole; wherein, the terminal assembly... The tab contains aluminum, manganese, and / or silicon. In a single tab layer, the mass percentage of aluminum is not less than 96%, and the mass percentage of manganese and / or silicon is a%. A resistance test point is formed on the non-welded area of ​​the tab. The first solder mark area is located between the electrode assembly and the resistance test point. The resistance between the electrode assembly and the resistance test point is b, where b is in mΩ. The thickness of the tab layer is c, where c is in mm. a, b, and c satisfy 0.006 ≤ b × a / c ≤ 12.5.

[0006] Beneficial effects: The mass ratio of manganese and / or silicon (a%), the resistance (b) between the terminal assembly and the resistance test point, and the thickness (c) of the tab layer satisfy 0.006 ≤ b × a / c ≤ 12.5. This ensures the overcurrent capacity between the terminal assembly and the tab, avoids battery voltage jumps, and guarantees battery reliability while reducing the risk of lithium plating. Specifically, if the value of b×a / c is too large, under the influence of the high temperature during welding of the tab and terminal assembly and the cooling and contraction of the first solder area, large pores will be generated in the first solder area. This will increase the impedance during overcurrent between the tab and terminal assembly. Furthermore, when the battery is subjected to vibration, the tab layer is prone to breakage, causing the electrical connection between the tab and terminal assembly to fail, affecting the overcurrent capacity between the tab and terminal assembly, and causing the output voltage to jump during battery use, thus affecting battery performance. If the value of b×a / c is too small, the strengthening effect of manganese and / or silicon on the tab layer is insufficient, making the tab layer more brittle. The foil connection between the tab layer and the cell body will result in insufficient foil strength. During battery charging and discharging, the electrode sheet will expand, causing the foil to break easily, which will lead to poor current transmission, affecting lithium ion insertion and extraction, and causing lithium plating problems in the battery.

[0007] Secondly, the present invention also provides a battery pack, including the battery described above, and further including a base plate and a frame, the frame being arranged around the outer periphery of the base plate, the base plate and the frame being fixedly connected, the base plate and the frame enclosing a receiving space, the battery being disposed in the receiving space and fixedly connected to the base plate.

[0008] Beneficial effects: When the battery pack is subjected to vibration, it avoids voltage jumps among the batteries and large voltage differences between batteries. This prevents problems such as overcharging or undercharging of some batteries during charging and discharging, thus ensuring the overall consistency of the batteries during charging and discharging, thereby ensuring the cycle life of the batteries. It also avoids thermal runaway caused by heat accumulation in some batteries, thus ensuring the safety performance of the battery pack.

[0009] Thirdly, the present invention also provides an electrical device including the aforementioned battery pack. Attached Figure Description

[0010] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1The image shows the welded and non-welded areas of the tab and pole assembly under CT scan. Figure 2 This is a schematic diagram of the test of resistor b according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a welding method for the tab and terminal assembly of a battery according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the first and second layers of the tab portion according to an embodiment of the present invention; Figure 5 for Figure 3 A top view of the battery shown; Figure 6 for Figure 5 The diagram shows a structure when the tab is eccentrically positioned relative to the cell body. Figure 7 This is a schematic diagram of the structure of the electrode portion in the embodiment of the present invention, which is in the form of a full electrode. Figure 8 This is a schematic diagram of another welding method for the tab and terminal assembly of the battery according to an embodiment of the present invention; Figure 9 for Figure 8 A schematic cross-sectional view of the tab and pole assembly in the yz plane; Figure 10 This is a schematic diagram of another welding method for the tab and terminal assembly of the battery according to an embodiment of the present invention; Figure 11 for Figure 10 A schematic cross-sectional view of the tab and pole assembly in the yz plane; Figure 12 This is a schematic diagram showing that one side edge of the electrode lug in an embodiment of the present invention does not extend beyond the edge of the electrode post assembly located on the same side; Figure 13 This is a schematic diagram showing that both sides of the electrode lug of this embodiment of the invention extend beyond the edge of the electrode post assembly located on the same side; Figure 14 This is a schematic diagram of the structure of the electrode and the first insulating layer according to an embodiment of the present invention; Figure 15 This is a schematic diagram of another welding method for the tab and terminal assembly of the battery according to an embodiment of the present invention; Figure 16 for Figure 15 A top view of the battery shown; Figure 17 This is a schematic diagram of another welding method for the tab and terminal assembly of the battery according to an embodiment of the present invention; Figure 18 for Figure 17 A top view of the battery shown; Figure 19 This is a schematic diagram of the structure of a bending area of ​​the tab portion according to an embodiment of the present invention; Figure 20 This is a schematic diagram of another bending region of the electrode lug in an embodiment of the present invention; Figure 21 This is a schematic diagram of the structure of the electrode sheet with reinforcing ribs according to an embodiment of the present invention; Figure 22 This is a schematic diagram of the structure of the battery cell and the second insulating layer according to an embodiment of the present invention; Figure 23 This is a schematic diagram of the structure of the first solder area extending to the first end of the electrode tab in an embodiment of the present invention; Figure 24 A schematic diagram of the structure in an embodiment of the present invention showing that the first solder area and the first end of the electrode tab are spaced apart. Figure 25 This is a schematic diagram of the welding structure of the electrode lug and the electrode post body according to an embodiment of the present invention; Figure 26 This is a schematic diagram of the welding structure of the electrode tab and the adapter piece according to an embodiment of the present invention; Figure 27 This is a schematic diagram of a structure in which a flux sheet is provided on the electrode tab in an embodiment of the present invention; Figure 28 This is a schematic diagram of the structure when the electrode tab is extended to the side according to an embodiment of the present invention; Figure 29 This is a schematic diagram of the structure when the tab is protruding according to an embodiment of the present invention; Figure 30 This is a schematic diagram of the structure of the electrode body when it is located on the large surface of the battery according to an embodiment of the present invention; Figure 31 This is a schematic diagram of the structure of the adapter piece with the first piece and the second piece before bending, according to an embodiment of the present invention. Figure 32 This is a schematic diagram of the structure of the adapter piece having a first piece and a second piece connecting the electrode lug and the electrode post body according to an embodiment of the present invention; Figure 33 This is a schematic diagram of a structure with a circular first cross-section according to an embodiment of the present invention; Figure 34 This is a schematic diagram of a structure with an elliptical first cross-section according to an embodiment of the present invention; Figure 35 This is a schematic diagram of a structure with an elongated oval (racetrack-shaped) first cross section according to an embodiment of the present invention; Figure 36 This is a schematic diagram of a structure with a square first cross section according to an embodiment of the present invention; Figure 37 This is a schematic diagram of the structure in which the protrusion and the cover plate are integrally formed according to an embodiment of the present invention; Figure 38This is a schematic diagram of the structure of the protrusion and the cover plate being welded according to an embodiment of the present invention; Figure 39 This is a schematic diagram of a structure in which the folded edge is continuously arranged circumferentially according to an embodiment of the present invention; Figure 40 This is a schematic diagram of the structure of the folded edge segmented in the circumferential direction according to an embodiment of the present invention; Figure 41 This is a schematic diagram of the structure of the pole body disposed in the housing according to an embodiment of the present invention; Figure 42 This is a schematic diagram of the structure of the electrode tab of the present invention, which is folded from one edge of the adapter piece to the side away from the battery cell body and then welded. Figure 43 This is a schematic diagram showing the unfolding of the electrode sheet forming the wound layer according to an embodiment of the present invention; Figure 44 This is a schematic diagram of the tab layer structure according to an embodiment of the present invention; Figure 45 This is a schematic diagram of the electrode structure according to an embodiment of the present invention; Figure 46 This is a schematic diagram illustrating the area of ​​the solder area of ​​the tab and pole assembly along the z-direction and the area of ​​the tab along the z-direction in an embodiment of the present invention. Figure 47 This is a schematic diagram of the segmented bonding wire structure according to an embodiment of the present invention; Figure 48 This is a schematic diagram of the continuous bonding wire structure according to an embodiment of the present invention; Figure 49 This is a schematic diagram of the structure of the first type of battery according to an embodiment of the present invention; Figure 50 for Figure 49 The front view of the battery shown; Figure 51 for Figure 50 A cross-sectional view along the AA direction; Figure 52 for Figure 51 A magnified view of a portion of point B in the middle; Figure 53 This is a schematic diagram of the structure of a second type of battery (casing not shown) according to an embodiment of the present invention; Figure 54 for Figure 53 A top view of the battery shown; Figure 55 for Figure 54 A cross-sectional view along the CC direction; Figure 56 for Figure 55 A magnified view of a portion of point D in the middle; Figure 57This is a schematic diagram of the structure of the third type of battery according to an embodiment of the present invention; Figure 58 for Figure 57 A top view of the battery shown; Figure 59 for Figure 58 A cross-sectional view along the EE direction; Figure 60 for Figure 59 A magnified view of a portion of point F in the middle; Figure 61 This is a schematic diagram of the structure of the fourth type of battery according to an embodiment of the present invention; Figure 62 for Figure 61 A top view of the battery shown; Figure 63 for Figure 62 Cross-sectional view along the GG direction; Figure 64 for Figure 63 A magnified view of a portion of point H in the middle; Figure 65 This is a schematic diagram of the structure of the fifth type of battery according to an embodiment of the present invention; Figure 66 for Figure 65 A top view of the battery shown; Figure 67 for Figure 66 Sectional view along direction II; Figure 68 for Figure 67 A magnified view of a portion of point J in the middle; Figure 69 This is a schematic diagram of the structure of the sixth type of battery according to an embodiment of the present invention; Figure 70 for Figure 69 A top view of the battery shown; Figure 71 for Figure 70 A cross-sectional view along the KK direction; Figure 72 for Figure 71 A magnified view of a portion of point L in the middle; Figure 73 This is a schematic diagram of the structure of a battery with square electrode posts according to an embodiment of the present invention; Figure 74 This is a schematic diagram of the structure of the racetrack-shaped terminal block battery according to an embodiment of the present invention; Figure 75 This is a schematic diagram of the cylindrical battery structure according to an embodiment of the present invention; Figure 76 This is a schematic diagram of the tab portion of a cylindrical battery according to an embodiment of the present invention; Figure 77This is a schematic diagram of the structure of a battery pack according to an embodiment of the present invention; Figure 78 This is a schematic diagram of the structure of an electrical device according to an embodiment of the present invention.

[0012] Explanation of reference numerals in the attached figures: 1. Outer shell; 11. Protrusion; 111. Folded edge; 112. Connecting edge; 12. Shell; 13. Cover plate; 14. Through hole; 2. Terminal assembly; 21. Terminal body; 211. First cross section; 2111. Straight section; 2112. Arc section; 22. Adapter piece; 221. First piece; 222. Second piece; 223. Welding surface; 224. First edge; 3. Cell; 31. Cell body; 311. Sheet; 3111. Current collector; 3112. Active material layer; 32. Tab; 321 3211. First layer; 3212. Second layer; 3213. Reinforcing rib; 3214. Polymer layer; 3215. Conductive layer; 322. Bending area; 3221. Crease; 33. Electrode; 34. First insulating layer; 4. First solder mark area; 5. Second sub-solder mark area; 6. Third sub-solder mark area; 7. Second insulating layer; 71. Adhesive area; 72. Non-adhesive area; 8. Flux sheet; 9. Solder wire; 10. First sub-solder mark area; 100. Battery pack; 110. Battery; 1000. Electrical equipment. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] The following is combined with Figures 1 to 78 The following describes embodiments of the present invention.

[0015] According to an embodiment of the present invention, a battery is provided, comprising: a casing 1; an electrode assembly 2 disposed on the casing 1; and a battery cell 3 disposed within the casing 1. The battery cell 3 includes a battery cell body 31 and a tab portion 32 extending from at least one end of the battery cell body 31. The tab portion 32 is welded to the electrode assembly 2 to form a first solder area 4. The tab portion 32 includes a plurality of stacked tab layers 321. The tab portion 32 contains aluminum, manganese, and / or silicon. The mass percentage of aluminum in a single tab layer 321 is not less than 96%, and the mass percentage of manganese and / or silicon is a%. A resistance test point is formed on the non-welded area of ​​the tab portion 32. The first solder area 4 is located between the electrode assembly 2 and the resistance test point. The resistance between the electrode assembly 2 and the resistance test point is b, where b is in mΩ. The thickness of the tab layer 321 is c, where c is in mm. a, b, and c satisfy 0.004 ≤ b × a / c ≤ 15.

[0016] The battery of this embodiment ensures that the mass percentage of manganese and / or silicon is a%, the resistance between the terminal assembly 2 and the resistance test point is b, and the thickness of the tab layer 321 is c, which satisfies 0.004≤b×a / c≤15. This ensures the overcurrent capacity between the terminal assembly 2 and the tab 32, avoids battery voltage jumps, and guarantees battery reliability while reducing the risk of lithium plating.

[0017] After numerous studies, researchers discovered that the large pressure difference between the batteries inside the battery pack is mainly due to the high resistance generated in the welding area between the battery tabs and terminals, especially at the interface between the welded and non-welded areas where large pores are prone to occur (see [link]). Figure 1 When the battery is charging or discharging or subjected to vibration, the tabs are prone to breakage, causing voltage fluctuations and affecting the stability of the battery's output voltage, thus impacting battery performance.

[0018] Specifically, if the value of b×a / c is too large, under the influence of the high temperature during welding of the tab 32 and the terminal assembly 2, and the cooling and contraction of the first solder area 4, large pores will be generated in the first solder area 4. This will increase the impedance during overcurrent between the tab 32 and the terminal assembly 2. Furthermore, when the battery is subjected to vibration, the tab layer 321 is prone to breakage, causing the electrical connection between the tab 32 and the terminal assembly 2 to fail, affecting the overcurrent capacity between the tab 32 and the terminal assembly 2, resulting in voltage fluctuations during battery use and affecting battery performance. If the value of b×a / c is too small, the strengthening effect of manganese and / or silicon on the tab layer 321 will be insufficient, making the tab layer 321 more brittle. Since the foil of the tab layer 321 and the cell body 31 is connected, the foil strength will be insufficient. During battery charging and discharging, the electrode 33 will expand, causing the foil to break easily, leading to poor current transmission, affecting lithium ion insertion and extraction, and causing lithium plating problems in the battery.

[0019] Optionally, the mass percentage of manganese and / or silicon a%, the resistance b between the electrode assembly 2 and the resistance test point, and the thickness c of the tab layer 321 satisfy 0.2 ≤ b × a / c ≤ 7.5.

[0020] Optionally, the value of b×a / c can be 0.004, 0.0045, 0.005, 0.006, 0.008, 0.009, 0.01, 0.012, 0.015, 0.018, 0.02, 0.025, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, or 0.1. 5, 0.16, 0.2, 0.5, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 13.6, 14, 14.5, 15, any value or a value between any two values.

[0021] Researchers discovered that after the tab 32 and the terminal assembly 2 are welded together to form a weld mark, pores can form inside the weld mark, especially at the junction of the weld mark and the adjacent non-welded area. When the number of pores increases or the pores become larger, the tab 32 is prone to fracture at the junction of the weld mark and the non-welded area under tensile force after the battery is subjected to stress. This leads to an increase in impedance between the tab 32 and the terminal assembly 2, a decrease in the overcurrent capacity between them, and a voltage drop in the battery, i.e., a voltage jump. Furthermore, in related technologies, for the positive electrode tab (aluminum), manganese (Mn) and / or silicon (Si) are usually added to the material to enhance the mechanical properties of the aluminum alloy. However, since the boiling points of manganese and silicon are lower than those of other elements in the aluminum alloy, they tend to segregate and aggregate. Therefore, under the high temperature of welding, manganese and silicon rapidly vaporize to form pores, which easily leads to the formation of large pores, further increasing the risk of the tab 32 breaking under stress. In addition, after the tab 32 and the pole assembly 2 are welded to form a welding area, shrinkage deformation will occur during the cooling process of the welding area, resulting in the formation of pores at the junction of the welding area and the non-welding area. If the tab layer 321 has low shrinkage resistance, it will result in the formation of large pores at the junction of the welding area and the non-welding area.

[0022] Therefore, in this embodiment, by reasonably controlling the relationship between the mass ratio of manganese and / or silicon (a%), the resistance (b) between the electrode assembly 2 and the resistance test point, and the thickness (c) of the tab layer 321, it is possible to avoid large pores in the welding of the tab 32 and the electrode assembly 2, so as to prevent the tab 32 from breaking during the charging and discharging process or after vibration, causing voltage jumps in the battery and affecting the stability of the battery output voltage, thus affecting the use of the battery. At the same time, it is possible to ensure the structural strength of the electrode 33 of the cell 3 and reduce the risk of lithium plating in the battery.

[0023] It is worth noting that the value of the mass percentage 'a%' of manganese and / or silicon mentioned above can be understood as follows: if only manganese is added to the tab 32, then 'a%' is the mass percentage of manganese; if only silicon is added to the tab 32, then 'a%' is the mass percentage of silicon; if both manganese and silicon are added to the tab 32, then 'a%' is the sum of the mass percentages of manganese and silicon.

[0024] Furthermore, the mass percentage (a%) of manganese and / or silicon can be obtained by, but is not limited to, the following methods: Method 1: Inductively Coupled Plasma Method (1) Sample preparation: The tab layer 321 sample is pretreated appropriately, such as by dissolving it in a specific acid solution to release the analyte. For example, aqua regia is used to dissolve the sample, or a specific mixed acid system is used for digestion to ensure effective release of the analyte.

[0025] (2) Analytical methods: The main analytical methods of ICP-OES include the standard curve method and the internal standard method. The standard curve method calculates the content of each element in the sample by plotting the relationship between the concentration of the standard solution and the emission intensity at the corresponding wavelength and comparing the emission intensity of the sample solution with the standard curve. The internal standard method selects an element with similar chemical properties to the analyte and a constant content in the sample as an internal standard. By comparing the emission intensity ratio of the analyte and the internal standard element, the influence of factors such as sample composition and experimental conditions is eliminated.

[0026] Method 2: X-ray fluorescence spectroscopy (1) Sample preparation: First, the tab layer 321 sample needs to be properly treated to facilitate X-ray penetration and excitation of fluorescence. This may include steps such as cutting, grinding, and polishing to ensure that the sample surface is flat and free of contamination.

[0027] (2) X-ray excitation: High-energy X-rays are used to irradiate the sample surface to excite the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the types of elements, thus allowing us to determine which elements are contained in the sample.

[0028] (3) Spectral collection and analysis: X-rays reflected from the sample surface and fluorescence spectra are collected using a spectrometer. The type and content of elements can be determined by the position and intensity of characteristic spectral lines.

[0029] (4) Matrix effect correction: Due to the interaction between various elements in the tabular layer 321 (matrix effect), the collected spectral data needs to be corrected to eliminate the influence of this interaction on the analysis results and improve the accuracy of the analysis.

[0030] (5) Interpretation of results: Based on the corrected data, the content of each element in the tab layer 321 can be calculated, and its performance and quality can be evaluated.

[0031] Specifically, in this embodiment, the mass percentage a% of manganese and / or silicon is detected by method two (X-ray fluorescence spectrometry).

[0032] It is worth noting that, such as Figure 2 As shown, when measuring resistance b, there is a resistance test point on the non-soldering area of ​​the tab 32, and another resistance test point on the side of the electrode assembly 2 away from the tab 32. The first solder area 4 is located between the two resistance test points. Specifically, an internal resistance meter is used, with one end connected to the resistance test point on the non-soldering area of ​​the tab 32 and the other end connected to the resistance test point on the side of the electrode assembly 2 away from the tab 32, to obtain resistance b. Furthermore, the distance between the resistance test point on the non-soldering area of ​​the tab 32 and the boundary between the soldering and non-soldering areas is within 10mm.

[0033] It should be further noted that this application does not limit the adjustment of resistance b. Specifically, the value of resistance b can be adjusted by adjusting the welding conditions during the welding process of the tab 32 and the electrode assembly 2, such as the welding power and the pressing force of the welding fixture. Specifically, the welding power ranges from 700W to 1300W, and the pressing force ranges from 200N to 400N.

[0034] It is worth noting that this application does not limit the test method for the thickness c of the tab layer 321; specifically, a thickness gauge can be used for measurement.

[0035] It is worth noting that the first soldering area 4 can be a continuous soldering area or a segmented soldering area with intervals.

[0036] In this embodiment, the tab 32 can be either a positive or negative tab. Specifically, when the battery is a lithium-ion battery, the tab 32 is a positive tab to avoid the risk of tab corrosion due to excessively low negative electrode potential. That is, when the battery is a lithium-ion battery, the positive tab is made of aluminum foil; when the battery is a sodium-ion battery, both the positive and negative tabs can be made of aluminum foil. It should be noted that when the tab layer 321 is made of aluminum foil, since aluminum foil is not pure aluminum, alloying elements in the aluminum alloy will vaporize and overflow, forming pores; when the welded area cools and shrinks, if the tensile strength (shrinkage resistance) of the tab layer 321 is relatively low, large pores are easily formed at the interface between the non-welded area and the welded area.

[0037] Specifically, in one embodiment, the mass percentage (a%) of manganese and / or silicon satisfies 0.01% ≤ a% ≤ 1.2%. This setting reduces the porosity of the first solder area to decrease the risk of battery voltage fluctuations, while also reducing the risk of lithium plating in the battery.

[0038] It is worth noting that if the value of 'a' is too large, under the influence of the high temperature during welding of the tab 32 and the terminal assembly 2, and the cooling and contraction of the first solder area 4, large pores will be generated in the first solder area 4. This will increase the impedance during overcurrent between the tab 32 and the terminal assembly 2. Furthermore, when the battery is subjected to vibration, the tab layer 321 is prone to breakage, causing the electrical connection between the tab 32 and the terminal assembly 2 to fail, affecting the overcurrent capacity between the tab 32 and the terminal assembly 2, resulting in voltage fluctuations during battery use and affecting battery performance. If the value of 'a' is too small, the strengthening effect of manganese and / or silicon on the tab layer 321 will be insufficient, making the tab layer 321 more brittle. Since the foil of the tab layer 321 and the cell body 31 is connected, the foil strength will be insufficient. During battery charging and discharging, the electrode 33 will expand, causing the foil to break easily, leading to poor current transmission, affecting lithium ion insertion and extraction, and causing lithium plating problems in the battery.

[0039] Optionally, the mass percentage of manganese and / or silicon, a%, satisfies 0.2% ≤ a% ≤ 0.9%.

[0040] Optionally, a% can be any value from 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, or a value between any two values.

[0041] Furthermore, in one embodiment, the mass percentage of manganese is 0.005% to 0.2%.

[0042] Optionally, the mass percentage of manganese is any one of the following values ​​or a value between any two: 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, and 0.2%.

[0043] Furthermore, in one embodiment, the mass percentage of silicon is 0.01% to 1%.

[0044] Optionally, the mass percentage of silicon is any one of 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, or 1%, or a value between any two of these.

[0045] Specifically, in one embodiment, the resistance b between the electrode assembly 2 and the resistance test point satisfies 0.008mΩ≤b≤0.1mΩ. This setting reduces the impedance between the tab 32 and the electrode assembly 2 during overcurrent while avoiding excessively high requirements on the welding process of the tab and the electrode assembly.

[0046] It is worth noting that if the value of b is too large, the impedance between the tab and the terminal assembly during overcurrent will be too high, affecting the overcurrent capacity of the tab and the terminal assembly. If the value of b is too small, the welding process requirements for the tab and the terminal assembly will be too high, affecting production efficiency and increasing production costs.

[0047] Optionally, the resistance b between the pole assembly 2 and the resistance test point satisfies 0.01mΩ≤b≤0.08mΩ.

[0048] Optionally, the value of b can be any value among 0.008mΩ, 0.01mΩ, 0.02mΩ, 0.03mΩ, 0.04mΩ, 0.05mΩ, 0.06mΩ, 0.07mΩ, 0.08mΩ, 0.09mΩ, and 0.1mΩ, or a value between any two values.

[0049] Specifically, in one embodiment, the thickness c of the tab layer 321 satisfies 0.006mm ≤ c ≤ 0.025mm. This setting ensures the structural strength of the tab layer to guarantee the shrinkage resistance of the non-welded areas, while reducing the welding difficulty of several tab layers.

[0050] It is worth noting that if the value of c is too large, the thickness of a single tab layer will be too large, making it difficult to weld multiple tab layers and affecting welding reliability. If the value of c is too small, the structural strength of the tab layer will be poor, resulting in lower shrinkage resistance in the non-welded area, increasing the risk of large pores at the junction of the first solder area 4 and the non-welded area, and increasing the risk of tab 32 breaking when the battery is subjected to vibration.

[0051] Optionally, the thickness c of the tab layer 321 satisfies 0.008mm≤c≤0.02mm.

[0052] Optionally, the value of c can be any one of 0.006mm, 0.008mm, 0.0085mm, 0.009mm, 0.01mm, 0.012mm, 0.015mm, 0.018mm, 0.02mm, 0.022mm, 0.024mm, or 0.025mm, or a value between any two of these values.

[0053] like Figures 69 to 72 As shown, the outer casing 1 has a lead-out through hole 14, the terminal assembly 2 is at least partially disposed in the lead-out through hole 14, and the tab portion 32 is at least partially located inside the lead-out through hole 14. At this time, the solder area is closer to the outside of the outer casing 1. When the battery is subjected to force, the force acting on the solder area is greater, and the risk of the tab portion 32 breaking will increase.

[0054] Furthermore, a, b, and c satisfy 0.006 ≤ b × a / c ≤ 12.5.

[0055] In one embodiment, such as Figure 4 As shown, the plurality of tab layers 321 include a first layer 3211 and a second layer 3212, with corresponding edges of the first layer 3211 and the second layer 3212 spaced apart along the y-direction. That is, there is a stagger between at least two tab layers 321, and the corresponding edges of the plurality of tab layers 321 are not completely aligned. Therefore, the edge of the first solder area 4 will be closer to the edge of some tab layers 321, resulting in a smaller area of ​​the remaining non-welded area and lower shrinkage resistance of the non-welded area. Consequently, larger pores are more likely to form at the junction of the first solder area 4 and the non-welded area. In this embodiment, a, b, and c are further configured to satisfy 0.0045 ≤ b × a / c ≤ 13, that is, the value of b × a / c is further controlled to further avoid the formation of excessively large pores at the junction of the first solder area 4 and the non-welded area, thereby ensuring the overcurrent capacity between the electrode assembly 2 and the tab portion 32, avoiding battery voltage jumps, and ensuring battery reliability.

[0056] Specifically, in one embodiment, such as Figure 4As shown, along the y-direction, the distance between the corresponding edges of the first layer 3211 and the second layer 3212 is d, which satisfies 0.1mm≤d≤8mm. This setting avoids large pores at the junction of the first solder area 4 and the non-soldering area, while reducing process requirements and ensuring production efficiency.

[0057] It is worth noting that if the value of d is too large, it will lead to severe misalignment of several tab layers 321. In order to ensure the welding area of ​​the first solder area 4 to guarantee the current carrying capacity, the edge of the first solder area 4 will be too close to the edge of some tab layers 321. Therefore, it will be easier for large pores to be generated at the junction of the first solder area 4 and the non-welded area, resulting in increased impedance between the tab 32 and the terminal assembly 2 during current carrying. Furthermore, when the battery is subjected to vibration, the tab layer 321 is prone to breakage, causing the electrical connection between the tab 32 and the terminal assembly 2 to fail, affecting the current carrying capacity between the tab 32 and the terminal assembly 2, and causing the output voltage of the battery to jump during use, affecting the battery's use. If the value of d is too small, it is necessary to ensure a high degree of alignment of each tab layer 321 during the cell 3 processing. Therefore, the requirements for the cell 3 processing technology will be too strict, which will be inconvenient for the production of the cell 3 and lead to a decrease in production efficiency.

[0058] Optionally, d can be any value from 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, or a value between any two of these values.

[0059] It is worth noting that distance d refers to the distance between the first layer 3211 and the second layer 3212 on one side, that is, the distance between the two sides of the first layer 3211 and the second layer 3212 located on the same side along the y direction.

[0060] In one embodiment, such as Figure 5 and Figure 6 As shown, along the y-direction, at least one edge of the tab 32 is spaced apart from the edge of the cell body 31 located on the same side. This reduces the connection area between the cell body 31 and the tab 32, meaning the stress-bearing area of ​​the tab 32 is reduced, leading to more concentrated stress and a higher risk of breakage, thus affecting the current-carrying capacity between the tab 32 and the terminal assembly 2. In this embodiment, a, b, and c are further optimized to satisfy 0.0045 ≤ b × a / c ≤ 10. This further reduces the porosity generated during welding of the tab 32 and the terminal assembly 2, lowering the risk of breakage of the tab 32 when the battery is subjected to vibration. This ensures the current-carrying capacity between the terminal assembly 2 and the tab 32, preventing voltage jumps and guaranteeing battery reliability.

[0061] Furthermore, in one embodiment, such as Figure 5 and Figure 6 As shown, along the y-direction, the two sides of the tab 32 and the edge of the cell body 31 on the same side are spaced apart.

[0062] Specifically, in one embodiment, such as Figure 5 and Figure 6 As shown, along the y-direction, the distance between one edge of the tab 32 and the edge of the cell body 31 on the same side is e1, and the distance between the other edge of the tab 32 and the edge of the cell body 31 on the same side is e2, satisfying 0.3≤e1 / e2≤1.7. It is worth noting that if the value of e1 / e2 is too large or too small, it indicates that the tab 32 is severely eccentric relative to the cell body 31 in the y-direction, and the side of the tab 32 closer to the edge of the cell body 31 experiences more concentrated stress, increasing the risk of breakage of the tab 32 at the junction of the first solder area 4 and the non-soldering area.

[0063] Optionally, e1 / e2 can take any value from 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 or a value between any two values.

[0064] Furthermore, in one embodiment, such as Figure 6 As shown, the distance e1 between one edge of the tab 32 and the edge of the cell body 31 on the same side, and the distance e2 between the other edge of the tab 32 and the edge of the cell body 31 on the same side, satisfy e1≠e2, and the value of c satisfies 0.008mm≤c≤0.025mm. When e1≠e2, it indicates that the tab 32 is eccentric relative to the cell body 31 in the y-direction, which increases the risk of breakage of the tab 32 at the junction of the first solder area 4 and the non-soldering area. Therefore, in this embodiment, by further limiting the value of c, the anti-shrinkage ability of the tab layer 321 can be further improved, the porosity generated at the junction of the first solder area 4 and the non-soldering area can be further reduced, and the risk of breakage of the tab 32 when the battery is subjected to vibration can be reduced.

[0065] As an alternative implementation method, such as Figure 7As shown, along the y-direction, the two side edges of the tab portion 32 are flush with the two side edges of the cell body 31. That is, the battery adopts a full tab form. Specifically, along the y-direction, the tab portion 32 occupies the entire width of the cell body 31. At this time, the force-bearing area of ​​the tab portion 32 is large, and the force is more uniform throughout the tab portion 32, reducing the risk of breakage of the tab portion 32 at the junction of the first solder area 4 and the non-soldering area. Therefore, in this embodiment, the value of c is further made to satisfy 0.006mm≤c≤0.02mm, which facilitates the welding of several tab layers 321, reduces welding heat, and reduces the porosity formed during the welding process.

[0066] In one embodiment, such as Figures 5 to 7 As shown, along the y-direction, at least one edge of the first solder area 4 is spaced apart from the edge of the tab 32 located on the same side. That is, at least one side of the first solder area 4 is not welded to the edge of the tab 32, thereby reducing the risk of porosity forming in the first solder area 4. Furthermore, in this embodiment, the value of c is set to 0.008mm≤c≤0.024mm, which facilitates the welding of several tab layers 321, reduces welding heat, and reduces porosity formed during the welding process.

[0067] Furthermore, in one embodiment, such as Figure 6 As shown, the battery cell 3 includes several layers of electrode sheets 33 stacked together. Adjacent electrode sheets 33 have opposite polarities, while adjacent electrode sheets 33 with the same polarity are disconnected. That is, the battery cell 3 in this embodiment is a stacked battery cell. Stacked battery cells are typically composed of positive electrode sheets, separators, and negative electrode sheets. For the stacked battery cell 3, the stacked battery cell can improve the overall space utilization rate inside the square battery. However, during the stacking process of the electrode sheets 33, the alignment between the electrode sheets 33 is poor, resulting in more severe misalignment of the tabs 32. Therefore, in this embodiment, along the y-direction, the distance between at least one edge of the first solder area 4 and the edge of the tab 32 on the same side is f, and the width of the tab layer 321 is t2, satisfying 0.015≤f / t2≤0.7. By limiting the distance between the edge of the first solder area 4 and the edge of the tab 32, the edge of the first solder area 4 and the edge of the tab 32 are sufficiently far apart, ensuring the area of ​​the remaining non-welded area, improving the shrinkage resistance of the non-welded area, and avoiding the generation of large pores at the junction of the first solder area 4 and the non-welded area.

[0068] Optionally, f / t2 can take any value from 0.015, 0.02, 0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.62, 0.65, 0.68, 0.7, or a value between any two values.

[0069] Furthermore, in one embodiment, such as Figures 5 to 7 As shown, along the y-direction, the two side edges of the first solder area 4 and the edge of the tab 32 on the same side are spaced apart. That is, both sides of the first solder area 4 are welded to the edge of the tab 32, thereby further reducing the risk of porosity in the first solder area 4. Furthermore, in this embodiment, the value of c is set to 0.0085mm≤c≤0.025mm, which facilitates the welding of several tab layers 321, reduces welding heat, and reduces porosity formed during the welding process.

[0070] Specifically, in one embodiment, such as Figure 5 As shown, along the y-direction, the distance between one edge of the first solder area 4 and the edge of the tab 32 on the same side is f1, and the distance between the other edge of the first solder area 4 and the edge of the tab 32 on the same side is f2, satisfying 0.5≤f1 / f2≤1.5. It is worth noting that if the value of f1 / f2 is too large or too small, it indicates that the first solder area 4 is severely eccentric relative to the tab 32 in the y-direction, and the edge of the first solder area 4 is closer to the edge of the tab 32 on one side, while the edge of the first solder area 4 is farther away from the edge of the tab 32 on the other side. This increases the risk of porosity and causes a significant difference in the stress capacity on both sides of the first solder area 4 along the y-direction. Even when the stress on the tab 32 is relatively small, the side of the first solder area 4 closer to the edge of the tab 32 is prone to breakage.

[0071] Optionally, f1 / f2 can take any value from 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5 or a value between any two values.

[0072] In one embodiment, such as Figure 8 and Figure 9 As shown, the first solder mark area 4 includes a first sub-solder mark area 10 and a second sub-solder mark area 5. Along the y direction, the second sub-solder mark area 5 is spaced apart from the first sub-solder mark area, and a, b and c satisfy 0.04≤b×a / c≤15.

[0073] Specifically, in this embodiment, such as Figure 9 As shown, the first sub-soldering area 10 welds the tab 32 and the pole assembly 2, and the second sub-soldering area 5 welds the tab 32 and the pole assembly 2.

[0074] It is worth noting that by setting up double-pass solder joints and using a step-by-step welding method to weld the tab 32 and the terminal assembly 2, the welding power of each solder joint can be reduced, thereby reducing the heat generated during welding and reducing the porosity of the first solder joint area 4. Therefore, further limiting the range of b×a / c values ​​can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several layers of tab layers 321, reducing welding heat and reducing the porosity formed during the welding process.

[0075] Furthermore, along the y-direction, the distance between the first sub-soldering area 10 and the second sub-soldering area 5 is i2, satisfying 2mm≤i2≤30mm. This configuration ensures the welding quality of the tab 32 and the terminal assembly 2, while also guaranteeing the welding area and current-carrying capacity of the tab 32 and the terminal assembly 2.

[0076] It is worth noting that if the value of i2 is too large, the distance between the second sub-soldering area 5 and the first sub-soldering area 10 will be too far. Given a fixed area available for welding in the electrode assembly 2, this will result in a smaller welding area for both areas, affecting the current-carrying capacity between the tab 32 and the electrode assembly 2. Conversely, if the value of i2 is too small, the distance between the second sub-soldering area 5 and the first sub-soldering area 10 will be too close, leading to potential overlap and welding defects. This will affect the connection strength and current-carrying capacity between the tab 32 and the electrode assembly 2.

[0077] Additionally, in another embodiment, such as Figure 10 and Figure 11 As shown, the first solder area 4 includes a first sub-soldering area 10 and a second sub-soldering area 5. Along the y-direction, the orthographic projection of the first sub-soldering area 10 on the surface of the tab 32 is located within the orthographic projection of the second sub-soldering area 5 on the surface of the tab 32. a, b and c satisfy 0.01≤b×a / c≤15.

[0078] Specifically, in this embodiment, such as Figure 11As shown, the first sub-soldering region 10 is welded to the tab 32 and the electrode post assembly 2, and the second sub-soldering region 5 is provided with the tab 32 welded to, so that the multiple layers of tab 321 are welded together. Further, the second sub-soldering region 5 is formed by ultrasonic welding, and the first sub-soldering region is formed by laser welding. Along the y-direction, the first sub-soldering region can completely fall within the second sub-soldering region 5; that is, the second sub-soldering region 5 is larger than the first sub-soldering region 10 along the y-direction.

[0079] It is worth noting that the tab 32 is pre-welded through the second sub-welding area 5 before being welded to the electrode post assembly 2. Pre-welding the tab 32 increases its structural strength, thereby further improving its resistance to shrinkage and reducing porosity at the junction of the first welding area 4 and the non-welded area, thus lowering the risk of breakage when the battery is subjected to vibration. Therefore, further limiting the range of b×a / c can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and facilitate the welding of multiple tab layers 321, reducing welding heat and porosity formed during the welding process.

[0080] In one embodiment, such as Figure 5 and Figure 12 As shown, along the y-direction, at least one edge of the tab 32 does not extend beyond the edge of the terminal post assembly 2 located on the same side. Therefore, during the welding of the tab 32 and the terminal post assembly 2, the terminal post assembly 2 can support the tab 32, thereby improving welding stability and reducing the formation of pores in the first solder area 4. Furthermore, in this embodiment, by ensuring that a, b, and c satisfy 0.005 ≤ b × a / c ≤ 12, the structural strength of the electrode 33 can be further improved, the risk of lithium plating in the battery can be reduced, and the welding of multiple tab layers 321 can be facilitated, reducing welding heat and reducing pores formed during the welding process.

[0081] Of course, as alternative implementation methods, such as Figure 7 and Figure 13 As shown, along the y-direction, both sides of the tab 32 extend beyond the edge of the terminal post assembly 2 on the same side. In this case, during welding of the tab 32 and the terminal post assembly 2, the terminal post assembly 2 does not support both sides of the tab 32, resulting in poor welding stability and making the first solder area 4 prone to porosity. Therefore, in this embodiment, a, b, and c satisfy 0.02≤b×a / c≤15 to further reduce porosity formed by the vaporization of manganese and / or silicon elements during welding. This also ensures the structural strength and shrinkage resistance of the tab layer 321, reduces porosity at the junction of the first solder area 4 and the non-welded area, and lowers the risk of tab 32 breakage when the battery is subjected to vibration.

[0082] It is worth noting that when the pole assembly 2 only includes the pole body 21, that is, the tab 32 is directly welded to the pole body 21, under normal circumstances, at least one edge of the tab 32 will extend beyond the same edge of the pole body 21.

[0083] In one embodiment, such as Figure 14 As shown, the battery cell 3 includes several layers of electrode sheets 33 stacked along the z-direction. Each electrode sheet 33 includes a sheet body 311 and a tab layer 321 extending from at least one end of the sheet body 311. The several layers of sheet bodies 311 form the battery cell body 31, and the several layers of tab layers 321 form a tab portion 32. A first insulating layer 34 is provided in the connection area between the sheet body 311 and the tab layer 321. By providing the first insulating layer 34, insulation is provided between adjacent electrode sheets 33 to avoid battery short circuit problems. Furthermore, when the first solder area 4 cools, shrinks, and deforms, the first insulating layer 34 fixes the position of the root of the tab layer 321 (the end connected to the sheet body 311), that is, fixes the non-soldering area, resulting in an increase in the porosity between the first solder area 4 and the non-soldering area. Furthermore, in this embodiment, a, b, and c are made to satisfy 0.04≤b×a / c≤14.5, which further reduces the porosity formed by the vaporization of manganese and / or silicon elements during the welding process, and can ensure the structural strength and shrinkage resistance of the tab layer 321, reduce the porosity generated at the junction of the first solder area 4 and the non-welded area, and reduce the risk of breakage of the tab 32 when the battery is subjected to vibration.

[0084] It is worth noting that in this embodiment, the thickness c of the tab layer 321 is the thickness of a single tab.

[0085] It should be noted that the first insulating layer 34 refers to the tab adhesive, which can be aluminum oxide plus PVDF adhesive layer, used to achieve insulation protection between the positive and negative electrode plates; to prevent the negative electrode tab from being inserted in reverse and short-circuited with the positive electrode plate, or the positive electrode tab and the negative electrode plate from contacting each other, the first insulating layer 34 is set to avoid short-circuiting of the positive and negative electrodes.

[0086] Furthermore, in this embodiment, as Figure 14 As shown, along the x-direction, the first insulating layer 34 extends beyond the connection between the sheet 311 and the tab layer 321 and extends to the tab layer 321. This arrangement ensures the insulation effect between adjacent electrode sheets 33 and improves the overall structural strength of the tab portion 32. It also reduces the risk of the tab portion 32 breaking when the battery is subjected to vibration, and ensures the overcurrent capacity between the tab portion 32 and the terminal assembly 2.

[0087] It is worth noting that the z-direction is the stacking direction of several electrode layers, the x-direction is the lead-out direction of the electrode, and the y-direction is the direction that is perpendicular to both the x-direction and the z-direction.

[0088] Specifically, in this embodiment, such as Figure 14 As shown, along the x-direction, the distance by which the first insulating layer 34 extends beyond the connection point between the sheet 311 and the tab layer 321 is g, satisfying 0.5mm≤g≤8mm. This setting ensures the insulation effect between adjacent electrode sheets 33 while avoiding any impact on the welding process of the tab portion 32.

[0089] It is worth noting that if the value of g is too large, the distance between the first insulating layer 34 and the first solder area 4 may become too close, which may affect the soldering process of the tab 32. If the value of g is too small, the insulation effect of the first insulating layer 34 between adjacent electrode sheets 33 will be insufficient, and there is still a risk of battery short circuit.

[0090] Optionally, g can be any value from 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, or a value between any two of these values.

[0091] Specifically, in this embodiment, such as Figure 14 As shown, along the x-direction, the distance between the first insulating layer 34 and the first solder area 4 is h, which satisfies 10mm≤h≤50mm. This setting effectively improves the structural strength of the tab portion 32 while avoiding damage to the first insulating layer 34 caused by welding heat.

[0092] It is worth noting that if the value of h is too large, the length of the first insulating layer 34 on the tab 32 will be relatively short, which will have a limited effect on enhancing the structural strength of the tab 32. If the value of h is too small, the distance between the first insulating layer 34 and the first solder area 4 will be too close, and the heat during the welding of the tab 32 and the pole assembly 2 will easily damage the first insulating layer 34, thereby affecting the insulation effect between adjacent pole pieces 33.

[0093] Optionally, h can be any value among 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, and 50mm, or a value between any two of these values.

[0094] In one embodiment, such as Figure 15 and Figure 16 As shown, the first solder area 4 includes a first sub-solder area 10 and a third sub-solder area 6. Along the x-direction, the first sub-solder area 10 and the third sub-solder area 6 are spaced apart, and a, b and c satisfy 0.1≤b×a / c≤15.

[0095] Specifically, in this embodiment, such as Figure 15As shown, the first sub-soldering area 10 welds the tab 32 and the pole post assembly 2, and the third sub-soldering area 6 welds the tab 32 and the pole post assembly 2.

[0096] It is worth noting that by setting up double-pass solder joints and using a step-by-step welding method to weld the tab 32 and the terminal assembly 2, the welding power of each solder joint can be reduced, thereby reducing the heat generated during welding and reducing the porosity of the first solder joint area 4. Therefore, further limiting the range of b×a / c values ​​can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several layers of tab layers 321, reducing welding heat and reducing the porosity formed during the welding process.

[0097] It should be noted that, as Figure 15 and Figure 16 As shown, the third sub-soldering area 6 is located on the side of the first sub-soldering area 10 that is close to the cell body 31.

[0098] Furthermore, in this embodiment, as Figure 16 As shown, along the x-direction, the distance between the third sub-soldering area 6 and the first sub-soldering area 10 is i1, satisfying 0≤i1≤5mm. This setting ensures the welding quality of the tab 32 and the pole assembly 2, while also guaranteeing the welding area of ​​the tab 32 and the pole assembly 2, and ensuring the current-carrying capacity of the tab 32 and the pole assembly 2.

[0099] It is worth noting that if the value of i1 is too large, the distance between the third sub-soldering area 6 and the first sub-soldering area 10 will be too far. Given a fixed area available for welding in the electrode assembly 2, this will result in a smaller welding area for both areas, affecting the current-carrying capacity between the tab 32 and the electrode assembly 2. Conversely, if the value of i1 is too small, the distance between the third sub-soldering area 6 and the first sub-soldering area 10 will be too close, leading to potential overlap and welding defects. This will affect the connection strength and current-carrying capacity between the tab 32 and the electrode assembly 2.

[0100] Optionally, i1 can be any value from 0, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or a value between any two of these values.

[0101] Additionally, in another embodiment, such as Figure 17 and Figure 18As shown, the first solder area 4 includes a first sub-solder area 10 and a third sub-solder area 6. Along the x-direction, the orthographic projection of the first sub-solder area 10 on the surface of the tab 32 is located within the orthographic projection of the third sub-solder area 6 on the surface of the tab 32. a, b and c satisfy 0.09≤b×a / c≤14.

[0102] Specifically, in this embodiment, such as Figure 17 As shown, the first sub-soldering region 10 is welded to the tab 32 and the electrode post assembly 2, and the third sub-soldering region 6 is provided with the tab 32 welded to, so that the multiple tab layers 321 are welded together. Further, the third sub-soldering region 6 is formed by ultrasonic welding, and the first sub-soldering region 10 is formed by laser welding. Along the x-direction, the first sub-soldering region 10 can completely fall within the third sub-soldering region 6; that is, the dimension of the third sub-soldering region 6 along the x-direction is larger than the dimension of the first sub-soldering region 10 along the x-direction.

[0103] It is worth noting that the tab 32 is pre-welded (which can be ultrasonic welding) through the third sub-welding area 6 before being welded to the electrode assembly 2. Pre-welding the tab 32 increases its structural strength, thereby further improving its resistance to shrinkage and reducing porosity at the junction of the first welding area 4 and the non-welded area, thus lowering the risk of breakage when the battery is subjected to vibration. Therefore, further limiting the range of b×a / c can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and facilitate the welding of multiple tab layers 321, reducing welding heat and porosity formed during the welding process.

[0104] In one embodiment, such as Figure 19 and Figure 20 As shown, a bending region 322 is formed in the tab portion 32 between the first solder area 4 and the cell body 31. By setting the bending region 322, the stress on the first solder area 4 can be buffered, reducing the stress on the first solder area 4 and reducing the risk of delamination of the tab portion 32 at the junction of the first solder area 4 and the non-soldering area. This ensures the overcurrent capacity between the tab portion 32 and the terminal assembly 2 and avoids the occurrence of battery voltage jump phenomena.

[0105] It is worth noting that the tab 32 between the cell body 31 and the first solder area 4 can be bent once (see [link]). Figure 19 Or perform multiple bends (see [link]). Figure 20 ).

[0106] Therefore, the bending area 322 has a crease 3221 (see also) Figure 19 ) or it has several creases spaced along the x-direction 3221 (see also) Figure 20 ).like Figure 20 As shown, along the x-direction, the shortest distance between the crease 3221 closest to the first solder area 4 and the first solder area 4 is l1, which satisfies 2mm≤l1≤10mm. This setting provides a buffering effect for the first solder area 4 while ensuring the heat dissipation effect of the tab 32.

[0107] It is worth noting that if the value of l1 is too small, the heat dissipation capacity of the bending area 322 will be poor. When the bending area 322 is too close to the first solder area 4, the heat from the bending area 322 and the first solder area 4 will be superimposed, resulting in poor heat dissipation of the tab 32, increasing the risk of thermal runaway and affecting the battery's safety performance. If the value of l1 is too large, the distance between the bending area 322 and the first solder area 4 will be too far, and the buffering effect of the bending area 322 on the first solder area 4 will be insufficient. This will make the edge of the first solder area 4 prone to tearing of the tab 32, resulting in an excessively high fault rate of the tab 32. This will affect the overcurrent capacity between the tab 32 and the terminal assembly 2, causing the output voltage of the battery to jump during use and affecting the battery's performance.

[0108] Optionally, l1 can be any value from 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, or a value between any two of these values.

[0109] In one embodiment, such as Figure 21 As shown, at least one tab layer 321 is provided with reinforcing ribs 3213. By providing reinforcing ribs 3213 on the tab layer 321, the structural strength of the tab portion 32 can be improved, the shrinkage deformation of the first solder area 4 during the cooling process can be reduced, thereby reducing the porosity between the first solder area 4 and the non-welded area, and reducing the pulling of the cell body 31 on the first solder area 4 through the tab portion 32, reducing the risk of delamination of the tab portion 32, and thus ensuring the overcurrent capacity between the tab portion 32 and the terminal assembly 2, avoiding the occurrence of battery voltage jump phenomena. Furthermore, in this embodiment, making a, b, and c satisfy 0.1≤b×a / c≤13 can further improve the structural strength of the electrode sheet 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several tab layers 321, reduce welding heat, and reduce the porosity formed during the welding process.

[0110] It is worth noting that the reinforcing rib 3213 can be a recess provided on the tab layer 321 (i.e., the current collector 3111).

[0111] Preferably, each tab layer 321 is provided with a reinforcing rib 3213.

[0112] It is worth noting that, in one embodiment, please refer to... Figure 21 The tab layer 321 has a plurality of reinforcing ribs 3213 spaced apart along the y-direction, and each reinforcing rib 3213 extends along the x-direction. Further, a single continuous reinforcing rib 3213 or multiple segmented reinforcing ribs 3213 can be provided along the x-direction. Of course, in other alternative embodiments, the reinforcing ribs 3213 can also have other shapes and structures, such as wavy lines or serrated shapes.

[0113] Specifically, in this embodiment, such as Figure 21 As shown, the reinforcing rib 3213 and the first weld area 4 are spaced apart. That is, the first weld area 4 and the reinforcing rib 3213 do not overlap, so as to avoid the reinforcing rib 3213 affecting the welding process of the first weld area 4.

[0114] Specifically, in this embodiment, such as Figure 21 As shown, the cell body 31 includes several layers of sheets 311 stacked along the z-direction, with tab layers 321 connected to the sheets 311. Along the x-direction, reinforcing ribs 3213 are spaced apart at the connections between the sheets 311 and the tab layers 321. It is worth noting that if the reinforcing ribs 3213 are connected to the root near the tab portion 32, the structural strength of the tab portion 32 near the root will be too high, easily causing the active layer of the sheets 311 to detach. If this detached active layer falls into the battery, it can easily lead to a battery safety accident.

[0115] In one embodiment, such as Figure 22 As shown, a second insulating layer 7 is provided on the surface of the battery cell 3. One end of the second insulating layer 7 extends to the surface of the tab portion 32, and the other end extends to the surface of the battery cell body 31. By providing the second insulating layer 7, the tab portion 32 can be fixed, reducing the risk of vibration when the tab portion 32 is subjected to force, thereby reducing the risk of delamination of the tab portion 32. Furthermore, in this embodiment, a, b, and c are made to satisfy 0.15≤b×a / c≤13.5, which can further improve the structural strength of the electrode sheet 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several layers of tab layers 321, reduce welding heat, and reduce the porosity formed during the welding process.

[0116] It is worth noting that the second insulating layer 7 can be PVC tape. The second insulating layer 7 mainly serves to provide insulation protection for the surface of the battery cell 3.

[0117] Furthermore, in this embodiment, as Figure 22 As shown, the second insulating layer 7 covers at least a portion of the first solder area 4. This arrangement not only further enhances the limiting effect of the tab 32, but also protects the first solder area 4, preventing solder slag from falling off.

[0118] Furthermore, in this embodiment, as Figure 22 As shown, the second insulating layer 7 includes an adhesive region 71 and a non-adhesive region 72.

[0119] Specifically, the non-adhesive area 72 covers at least a portion of the bending area 322. This configuration reduces the tensile force exerted by the cell body 31 on the tab 32 when the tab 32 is bent, thereby reducing the risk of breakage of the tab 32 and improving the current-carrying capacity between the tab 32 and the terminal assembly 2.

[0120] Specifically, the non-adhesive area 72 covers at least part of the connection between the cell body 31 and the tab 32. This configuration reduces the tensile force exerted by the cell body 31 on the tab 32 when the tab 32 is bent, reduces the risk of breakage of the tab 32, and improves the current carrying capacity between the tab 32 and the terminal assembly 2.

[0121] Furthermore, in this embodiment, as Figure 22 As shown, along the x-direction, the total length of the bonding area 71 is k, satisfying 0.05≤j / k≤0.4. This setting reduces the tensile force exerted by the cell body 31 on the tab portion 32 while ensuring the bonding stability between the second insulation layer 7 and the cell 3.

[0122] It is worth noting that if the value of j is too small, the tensile force exerted by the cell body 31 on the tab 32 when bending the tab 32 will still be relatively large, which will lead to a relatively high risk of breakage of the tab 32. If the value of j is too large, it will easily result in a shorter length of the bonding area 71, and poor bonding stability between the second insulation layer 7 and the cell 3.

[0123] Optionally, j / k can take any value from 0.05, 0.08, 0.1, 0.15, 0.18, 0.2, 0.25, 0.28, 0.3, 0.35, 0.38, 0.4, or a value between any two values.

[0124] It should be noted that, along the x-direction, adhesive areas 71 are provided on both opposite sides of the non-adhesive area 72 (that is, the non-adhesive area 72 is connected between two adjacent adhesive areas 71), for bonding to the cell body 31 and the tab portion 32 respectively. Therefore, please refer to... Figure 22 Along the x-direction, the total length of the adhesive region 71 is the sum of the lengths of the two adhesive regions 71, that is, k = k1 + k2.

[0125] In one embodiment, such as Figure 24As shown, a solder area is formed on the tab 32, including a first solder area 4. Along the x-direction, the solder area is spaced apart from the end of the tab 32 furthest from the cell body 31. That is, the solder area is not soldered to the beginning of the tab 32 (the end opposite the root of the tab 32), giving the solder area better resistance to shrinkage during cooling, thereby reducing the risk of porosity during welding and lowering the risk of breakage of the tab 32. Furthermore, in this embodiment, a, b, and c satisfy 0.01 ≤ b × a / c ≤ 12, which can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several tab layers 321, reducing welding heat and porosity formed during welding.

[0126] Furthermore, in this embodiment, as Figure 24 As shown, along the x-direction, the distance between the first solder area 4 and the end of the tab 32 away from the cell body 31 is l, satisfying 0 < l ≤ 20 mm. This setting reduces the risk of porosity during soldering while ensuring the current carrying capacity of the first solder area 4 and reducing the risk of breakage of the tab 32.

[0127] It is worth noting that if the value of l is too large, the distance between the first solder area 4 and the beginning of the tab 32 will be too far, which may cause the distance between the first solder area 4 and the root of the tab 32 to be too close. The tensile force applied by the cell body 31 to the tab 32 will then act on the first solder area 4, potentially causing the tab 32 to tear. Alternatively, it may reduce the welding area of ​​the first solder area 4, resulting in lower current carrying capacity. If the value of l is too small, the distance between the first solder area 4 and the beginning of the tab 32 will still be too close, leading to lower resistance to shrinkage during cooling of the first solder area 4, and a higher risk of porosity in the solder joint.

[0128] Optionally, l can be any value from 0.01mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, or a value between any two of these values.

[0129] Furthermore, in this embodiment, as Figure 24As shown, along the x-direction, the distance between the first solder area 4 and the end of the tab 32 near the cell body 31 is m, satisfying 0.3 ≤ l / m ≤ 1.7. That is, along the x-direction, the distance between the first solder area 4 and the beginning of the tab 32 is l, and the distance between the first solder area 4 and the root of the tab 32 is m. By limiting the range of l / m, the first solder area 4 is positioned near the middle of the tab 32 in the x-direction. During the cooling process of the first solder area 4, the force on both sides of the first solder area 4 along the x-direction is more uniform, reducing the excessive porosity between one side of the first solder area 4 and the non-soldering area, and reducing the risk of breakage of the tab 32.

[0130] Optionally, l / m can be any value from 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 or a value between any two values.

[0131] As an alternative implementation method, such as Figure 23 As shown, along the x-direction, the solder area extends to the end of the tab 32 away from the cell body 31. That is, the solder area is soldered to the beginning of the tab 32 (the end opposite to the root of the tab 32), which reduces the shrinkage resistance of the solder area during cooling, thereby increasing the risk of porosity in the weld and consequently increasing the risk of tab 32 breakage. Furthermore, in this embodiment, a, b, and c satisfy 0.006≤b×a / c≤12.5, further reducing the porosity formed by the vaporization of manganese and / or silicon elements during welding, and ensuring the structural strength and shrinkage resistance of the tab layer 321, reducing the porosity generated at the junction of the first solder area 4 and the non-welded area, and reducing the risk of tab 32 breakage when the battery is subjected to vibration.

[0132] It should be noted that the aforementioned soldering area refers to all soldering areas on the tab 32. That is, it may not only be the first soldering area 4, but may also include other soldering areas, such as pre-soldering areas (soldering areas that pre-solder several tab layers together). Taking the soldering area extending to the end of the tab 32 away from the cell body 31 as an example, in this case, it could be the first soldering area 4 soldered to the beginning of the tab 32, or it could be the pre-soldering area soldered to the beginning of the tab 32.

[0133] In one embodiment, such as Figure 25 As shown, the electrode assembly 2 includes an electrode body 21, which is directly welded to the tab 32. That is, the tab 32 is directly connected to the electrode body 21 without the need for an adapter 22, thus reducing the resistance during current transmission and increasing overcurrent.

[0134] Of course, in another embodiment, such as Figure 26 As shown, the electrode assembly 2 includes an electrode body 21 and an adapter plate 22. The electrode body 21 and the adapter plate 22 are welded together, and the adapter plate 22 is welded to the tab portion 32. That is, the adapter plate 22 serves as an intermediate component to achieve electrical connection between the tab portion 32 and the electrode body 21. The adapter plate can be made of a metal such as aluminum. Welding several layers of tab layers 321 to the adapter plate 22 results in better welding effect, improves welding strength and welding quality, and helps reduce porosity in the weld.

[0135] In one embodiment, such as Figure 27 As shown, a flux sheet 8 is provided on the side of the tab 32 facing away from the electrode assembly 2. By providing the flux sheet 8, the welding quality during the welding process can be improved, the risk of porosity during welding can be reduced, and the risk of breakage of the tab 32 can be reduced. Furthermore, in this embodiment, a, b, and c are made to satisfy 0.008≤b×a / c≤7, which can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several layers of tab layers 321, reduce welding heat, and reduce porosity formed during the welding process.

[0136] It is worth noting that the flux 8 can support the welding of the tab 32 and the pole assembly 2. The flux 8 is made of metal, specifically aluminum, copper, nickel, etc.

[0137] Specifically, in this embodiment, the flux sheet 8 contains aluminum, manganese, and / or silicon. This configuration further improves the welding effect between the flux sheet 8 and the tab 32, reducing the risk of porosity during welding and lowering the risk of breakage of both the tab 32 and the flux sheet 8. Furthermore, in this embodiment, ensuring that a, b, and c satisfy 0.05 ≤ b × a / c ≤ 13.6 further enhances the structural strength of the electrode 33, reduces the risk of lithium plating in the battery, and facilitates the welding of multiple tab layers 321, reducing welding heat and porosity formed during welding.

[0138] Furthermore, in this embodiment, the mass percentage of manganese and / or silicon in the flux 8 is n%, satisfying 0.01%≤n%≤1.2%. This setting ensures the structural strength of the flux 8 while preventing the formation of large pores in the flux 8 after welding.

[0139] It is worth noting that if the value of n is too large, manganese and silicon elements will rapidly vaporize and form pores under high welding temperature, which can easily lead to the formation of large pores and further increase the risk of flux sheet 8 breaking under stress; if the value of n is too small, the effect of improving the mechanical properties of aluminum alloy material will not be obvious, and it will be difficult to guarantee the structural strength of flux sheet 8.

[0140] Optionally, n% can be any value from 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, or a value between any two values.

[0141] Furthermore, in this embodiment, the mass percentage (n%) of manganese and / or silicon in the flux 8 and the mass percentage (a%) of manganese and / or silicon in the tab 32 satisfy 0.8 ≤ n / a ≤ 1.2. This setting avoids excessive differences in the mass percentages of manganese and / or silicon in the flux 8 and the tab 32, improving the welding quality of the flux 8 and the tab 32 while preventing large pores from forming in the flux 8 or the tab 32 during welding, thus reducing the risk of breakage of the flux 8 and the tab 32.

[0142] It is worth noting that the value of the mass percentage n% of manganese and / or silicon mentioned above can be understood as follows: if only manganese is added to the flux 8, then n% is the mass percentage of manganese; if only silicon is added to the flux 8, then n% is the mass percentage of silicon; if both manganese and silicon are added to the flux 8, then n% is the sum of the mass percentages of manganese and silicon.

[0143] Optionally, n / a can take any value from 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2 or a value between any two values.

[0144] In one embodiment, the adapter piece 22 comprises aluminum, manganese, and / or silicon. This configuration further improves the welding effect between the adapter piece 22 and the tab 32, reducing the risk of porosity during welding and lowering the risk of breakage of both the tab 32 and the adapter piece 22. Furthermore, in this embodiment, ensuring that a, b, and c satisfy 0.06 ≤ b × a / c ≤ 14 further enhances the structural strength of the electrode 33, reduces the risk of lithium plating in the battery, and facilitates the welding of multiple tab layers 321, reducing welding heat and minimizing porosity formed during welding.

[0145] Furthermore, in this embodiment, the mass percentage of manganese and / or silicon in the adapter piece 22 is 0%, satisfying 0.01% ≤ 0% ≤ 1.2%. This setting ensures the structural strength of the adapter piece 22 while preventing the formation of large pores in the adapter piece 22 after welding.

[0146] It is worth noting that if the value of o is too large, manganese and silicon elements will rapidly vaporize and form pores under high welding temperature, which can easily lead to the formation of large pores and further increase the risk of the adapter piece 22 breaking under stress. If the value of o is too small, the effect of improving the mechanical properties of aluminum alloy material will not be obvious, and it will be difficult to guarantee the structural strength of the adapter piece 22.

[0147] Optionally, o% can be any value from 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, or a value between any two values.

[0148] Furthermore, in this embodiment, the mass percentage of manganese and / or silicon in the adapter piece 22 (o%) and the mass percentage of manganese and / or silicon in the tab 32 (a%) satisfy 0.8 ≤ o / a ≤ 1.2. This setting avoids excessively large differences in the mass percentages of manganese and / or silicon in the adapter piece 22 and the tab 32, improving the welding quality of the adapter piece 22 and the tab 32 while preventing large pores from forming in the adapter piece 22 or the tab 32 during welding, thus reducing the risk of breakage of the adapter piece 22 and the tab 32.

[0149] It is worth noting that the value of the mass percentage of manganese and / or silicon mentioned above can be understood as follows: if only manganese is added to the adapter piece 22, then the value of 0% is the mass percentage of manganese; if only silicon is added to the adapter piece 22, then the value of 0% is the mass percentage of silicon; if both manganese and silicon are added to the adapter piece 22, then the value of 0% is the sum of the mass percentages of manganese and silicon.

[0150] Optionally, o / a can be any value from 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2 or a value between any two values.

[0151] In one embodiment, the electrode body 21 comprises aluminum, manganese, and / or silicon. This configuration further improves the welding effect between the electrode body 21 and the tab 32, or between the electrode body 21 and the adapter 22, reducing the risk of porosity in the electrode body 21 during welding, reducing the risk of breakage of the tab 32, and improving the current-carrying capacity of the tab 32 and the electrode assembly 2. Furthermore, in this embodiment, ensuring that a, b, and c satisfy 0.06 ≤ b × a / c ≤ 14 further improves the structural strength of the electrode 33, reduces the risk of lithium plating in the battery, and also facilitates the welding of multiple tab layers 321, reducing welding heat and minimizing porosity formed during welding.

[0152] Furthermore, in this embodiment, the mass percentage of manganese and / or silicon in the electrode body 21 is p%, satisfying 0.01%≤p%≤1.2%. This setting ensures the structural strength of the electrode body 21 while avoiding the formation of large pores in the electrode body 21 after welding.

[0153] It is worth noting that if the value of p is too large, manganese and silicon elements will rapidly vaporize and form pores under the high temperature of welding, which will easily lead to the formation of large pores and affect the current flow capacity between the tab 32 and the pole assembly 2; if the value of p is too small, the effect on improving the mechanical properties of the aluminum alloy material will not be obvious, and it will be difficult to ensure the structural strength of the pole body 21.

[0154] Optionally, p% can be any value from 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, or a value between any two values.

[0155] Furthermore, in this embodiment, the mass percentage p% of manganese and / or silicon in the electrode body 21 and the mass percentage a% of manganese and / or silicon in the tab 32 satisfy 0.8 ≤ p / a ≤ 1.2. This setting avoids excessive differences in the mass percentages of manganese and / or silicon in the electrode body 21 and the tab 32, improving the welding quality of the electrode body 21 and the tab 32 while preventing large pores from forming in the electrode body 21 or the tab 32 during welding. This reduces the risk of breakage in the tab 32, lowers the impedance during current transmission, and enhances the current-carrying capacity between the tab 32 and the electrode assembly 2.

[0156] It is worth noting that the value of the mass percentage p% of manganese and / or silicon can be understood as follows: if only manganese is added to the electrode body 21, then p% is the mass percentage of manganese; if only silicon is added to the electrode body 21, then p% is the mass percentage of silicon; if both manganese and silicon are added to the electrode body 21, then p% is the sum of the mass percentages of manganese and silicon.

[0157] Optionally, p / a can be any value from 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2 or a value between any two values.

[0158] In one embodiment, such as Figure 28 and Figure 29As shown, the end face of the tab 32 extending from the cell body 31 is positioned opposite to the side of the battery where the terminal body 21 is located. Specifically, the surface from which the tab 32 extends is parallel to the surface of the terminal body 21 on the battery, that is, the tab 32 extends towards the surface of the terminal body 21 on the battery. The housing 12 can have openings on two sides or one side. The terminal body 21 is mounted on the cover plate 13, and the cover plate 13 seals the opening of the housing 12, that is, the end face of the tab 32 is parallel to the surface of the cover plate 13. Of course, the terminal body 21 can also be mounted on the housing 12, with the end face of the tab 32 parallel to the surface of the housing 12. The battery shape can be cylindrical, prism-shaped, or quasi-prism-shaped. It is worth noting that the tab 32 and the electrode body 21 are located on the same side, and the force on the electrode body 21 is directly transmitted to the tab 32, resulting in greater stress on the tab 32. This increases the risk of tearing of the tab 32, and consequently, the risk of fracture of the tab 32. Therefore, in this embodiment, a, b, and c are set to 0.05 ≤ b × a / c ≤ 10. This further reduces the porosity formed by the vaporization of manganese and / or silicon during the welding process, and ensures the structural strength and shrinkage resistance of the tab layer 321. It also reduces the porosity generated at the junction of the first solder area 4 and the non-welded area, and lowers the risk of breakage of the tab 32 when the battery is subjected to vibration.

[0159] In another alternative embodiment, the end face of the battery cell body 31 extending from the tab 32 is set at a certain angle to the side of the battery where the terminal body 21 is provided. Specifically, for example... Figure 30 , Figures 49 to 52 As shown, with the tab 32 extending along the x-direction, the surface of the tab 32 perpendicular to the stacking direction is parallel to the side of the battery where the terminal body 21 is located. For example, the terminal body 21 is located on the large surface of the battery, and the tab 32 is parallel to the large surface of the battery and connected to the terminal body 21. In this case, the force on the terminal body 21 is directly transmitted to the tab 32, causing the tab 32 to be subjected to greater force, which increases the risk of tearing of the tab 32 and further increases the risk of delamination of the tab 32. Therefore, in this embodiment, a, b, and c are set to 0.05 ≤ b × a / c ≤ 11 to further reduce the porosity formed by the vaporization of manganese and / or silicon elements during the welding process, and to ensure the structural strength and shrinkage resistance of the tab layer 321, reduce the porosity generated at the junction of the first solder area 4 and the non-welded area, and reduce the risk of breakage of the tab 32 when the battery is subjected to vibration.

[0160] Furthermore, in this embodiment, as Figure 30 and Figure 51As shown, the tab 32 extends along the length of the cell body 31. At this time, the electrode post 21 is disposed on the large surface of the battery, and the large surface of the outer casing 1 and the large surface of the cell body 31 (referring to the surface with the largest area of ​​the cell body) are disposed on the same side. During battery charging and discharging, the large surface of the battery expands significantly, causing the electrode post 21 to experience greater force, resulting in a greater tensile force on the tab 32, thus increasing the risk of the tab 32 breaking. Furthermore, in this embodiment, the length of the cell body 31 is q. When q ≥ 300 mm, 0.05 ≤ b × a / c ≤ 10. By further limiting the range of b × a / c, the porosity formed by the vaporization of manganese and / or silicon elements during welding is further reduced, and the structural strength and shrinkage resistance of the tab layer 321 are guaranteed. This reduces the porosity generated at the junction of the first solder area 4 and the non-welded area, lowering the risk of the tab 32 breaking when the battery is subjected to vibration.

[0161] Optionally, q can be any value from 300mm, 350mm, 400mm, 450mm, 500mm, 550mm, 600mm, 650mm, 700mm, 750mm, 800mm, 850mm, 900mm, 950mm, and 1000mm, or a value between any two of these values. Of course, it can also be a value greater than 1000mm.

[0162] In another alternative embodiment, the end face of the cell body 31 extending from the tab 32 is set at a certain angle to the side of the battery where the terminal body 21 is provided. Specifically, for example... Figure 31 , Figure 32 as well as Figures 53 to 56As shown, with the tab 32 extending along the x-direction, the surface of the tab 32 perpendicular to the stacking direction is perpendicular to the side of the battery where the terminal body 21 is located. The adapter piece 22 includes a first piece 221 and a second piece 222 connected at a predetermined angle. The tab 32 is connected to the first piece 221 (the tab can be bent), and the second piece 222 is correspondingly positioned to the side of the battery where the terminal body 21 is located. The second piece 222 is connected to the terminal body 21. That is, the tab 32 and the terminal body 21 are located on opposite sides, connected via L. The shaped adapter 22 connects the tab 32 and the electrode body 21. In this case, the force on the electrode body 21 is not directly applied to the tab 32, reducing the stress on the tab 32 and lowering the risk of tearing. Furthermore, the electrode body 21 is located on the small facet of the battery, with the small facet of the outer casing 1 and the small facet of the cell 3 on the same side. During battery charging and discharging, the small facet of the battery expands less, further reducing the stress on the electrode body 21 and thus lowering the tensile force on the tab 32, reducing the risk of breakage. Therefore, in this embodiment, ensuring that a, b, and c satisfy 0.1 ≤ b × a / c ≤ 13 further improves the structural strength of the electrode 33, reduces the risk of lithium plating in the battery, and facilitates the welding of multiple tab layers 321, reducing welding heat and porosity formed during welding.

[0163] Specifically, the predetermined angle between the first piece 221 and the second piece 222 can be 80° to 100°.

[0164] It is worth noting that the surface of the tab 32 perpendicular to the stacking direction is the surface perpendicular to the z direction, which means the surface formed by the x and y directions enclosing the tab 32.

[0165] It is worth noting that the angle range in the above-mentioned "the end face of the battery cell body 31 extending from the tab 32 is set at a certain angle with the side of the battery where the terminal body 21 is provided" is 85° to 95°.

[0166] In one embodiment, such as Figure 33 As shown, the pole body 21 has a first cross-section 211 in the direction perpendicular to the axis. The first cross-section 211 is circular, and a, b, and c satisfy 0.15 ≤ b × a / c ≤ 14. That is, the pole body 21 is a cylindrical pole (see [reference]). Figure 57 Cylindrical electrodes experience more uniform stress, resulting in more even stress distribution to the tab 32. This avoids localized stress concentration in the tab 32 and reduces the risk of tearing. Therefore, by further limiting the range of b×a / c values, the structural strength of the electrode 33 can be further improved, reducing the risk of lithium plating in the battery. Furthermore, it facilitates the welding of multiple tab layers 321, reduces welding heat, and minimizes porosity formed during the welding process.

[0167] As an alternative implementation method, such as Figure 34 As shown, the pole body 21 has a first cross-section 211 in a direction perpendicular to the axis, and the first cross-section 211 is elliptical; or, as shown... Figure 35 As shown, the pole body 21 has a first cross-section 211 in a direction perpendicular to the axis. The first cross-section 211 is an oblong shape (also known as a racetrack shape, please refer to [reference]). Figure 74 Specifically, the outer contour of the first cross-section 211 includes two straight segments 2111 and two arc segments 2112. The two straight segments 2111 are arranged at intervals, and the two arc segments 2112 are respectively connected to the two ends of the two straight segments 2111 on the same side. This arrangement facilitates increasing the area of ​​the first cross-section 211, thereby improving the current-carrying capacity of the electrode body 21. However, in this embodiment, the torque force borne by the electrode body 21 is increased, increasing the risk of deformation under stress. The force on the electrode body 21 is transmitted to the tab 32, increasing the stress on the tab 32 and making it more prone to breakage. Therefore, in this embodiment, a, b, and c are made to satisfy 0.12≤b×a / c≤13, which further reduces the porosity formed by the vaporization of manganese and / or silicon elements during the welding process, and can ensure the structural strength and shrinkage resistance of the tab layer 321, reduce the porosity generated at the junction of the first solder area 4 and the non-welded area, and reduce the risk of breakage of the tab 32 when the battery is subjected to vibration.

[0168] As an alternative implementation method, such as Figure 36 As shown, the pole body 21 has a first cross-section 211 in a direction perpendicular to the axis. The first cross-section 211 is rectangular or square (see [reference]). Figure 73 In this embodiment, the assembly stability between the electrode body 21 and the battery casing 1 is higher, avoiding the torsion of the electrode body 21 under stress and causing the tab 32 to twist and deform, thus reducing the risk of tearing of the tab 32. Therefore, further, in this embodiment, making a, b, and c satisfy 0.08≤b×a / c≤10 can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several tab layers 321, reduce welding heat, and reduce the porosity formed during the welding process.

[0169] As an alternative implementation, the pole body 21 has a first cross-section 211 in a direction perpendicular to the axis, the aspect ratio of the first cross-section 211 being u, satisfying 1.1≤u≤10 and 0.06≤b×a / c≤7.5. For details, please refer to... Figure 34U = u1 / u2. It is worth noting that if the aspect ratio of the electrode body 21 is too large, the torque force borne by the electrode body 21 will be too large, which will lead to excessive stress on the tab 32 and an excessive risk of breakage. Therefore, by further limiting the range of b×a / c, the porosity formed by the vaporization of manganese and / or silicon elements during the welding process can be further reduced, and the structural strength and shrinkage resistance of the tab layer 321 can be guaranteed. This reduces the porosity generated at the junction of the first solder area 4 and the non-welded area, and lowers the risk of breakage of the tab 32 when the battery is subjected to vibration.

[0170] In one embodiment, such as Figure 37 , Figure 38 , Figure 41 as well as Figures 61 to 68 As shown, the battery also includes a casing 1, which has a first surface. An electrode post body 21 is disposed on the first surface. The casing 1 includes a protrusion 11 disposed on the first surface, forming a folded edge 111 that engages with the upper part of the electrode post body 21 away from the tab 32. This arrangement, by pressing and limiting the electrode post body 21 with the folded edge 111, reduces the impact of vibration on the electrode post body 21, thereby reducing the force transmitted to the tab 32 and lowering the risk of tearing of the tab 32. Furthermore, in this embodiment, a, b, and c satisfy 0.12 ≤ b × a / c ≤ 14, which can further improve the structural strength of the electrode sheet 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several tab layers 321.

[0171] It is worth noting that the folded edge 111 and the pole body 21 may not be directly attached. For example, an insulating element may be provided between the folded edge 111 and the pole body 21 to avoid short circuits and other insulation risks caused by the pole body 21 overlapping with the outer shell 1.

[0172] Furthermore, in this embodiment, as Figure 37 , Figures 61 to 64 As shown, the outer casing 1 also includes a main body, with the protrusion 11 integrally formed with the main body. This configuration increases the connection strength between the protrusion 11 and the main body, improves the limiting effect of the protrusion 11 on the electrode body 21, further reduces the vibration of the electrode body 21, thereby further reducing the force transmitted to the tab 32 and further reducing the risk of tearing of the tab 32. Furthermore, in this embodiment, a, b, and c satisfy 0.16 ≤ b × a / c ≤ 14, which further improves the structural strength of the electrode 33, reduces the risk of lithium plating in the battery, and also facilitates the welding of several tab layers 321, reduces welding heat, and reduces the porosity formed during the welding process.

[0173] Or, in another embodiment, such as Figure 38 , Figures 65 to 68As shown, the outer casing 1 also includes a main body, with a protrusion 11 welded to the main body. In this case, the connection strength between the protrusion 11 and the main body is relatively low, resulting in a relatively poor limiting effect of the protrusion 11 on the electrode body 21. This increases the vibration of the electrode body 21, leading to increased stress on the tab 32 and a relatively higher risk of tearing. Therefore, in this embodiment, a, b, and c satisfy 0.01 ≤ b × a / c ≤ 10 to further reduce the porosity formed by the vaporization of manganese and / or silicon elements during welding. This also ensures the structural strength and shrinkage resistance of the tab layer 321, reduces porosity at the junction of the first solder area 4 and the non-welded area, and lowers the risk of breakage of the tab 32 when the battery is subjected to vibration.

[0174] It is worth noting that, such as Figure 37 , Figure 38 , Figure 64 and Figure 68 As shown, the protrusion 11 includes a connecting edge 112 and a folded edge 111. The side of the connecting edge 112 near the tab 32 is fixedly connected to the main body, and the side of the connecting edge 112 away from the tab 32 is fixedly connected to the side of the folded edge 111. The folded edge 111 and the connecting edge 112 are arranged at a predetermined angle so that the folded edge 111 at least partially covers the side of the pole body 21 away from the tab 32.

[0175] Furthermore, in this embodiment, as Figure 39 As shown, the folded edge 111 is continuously arranged circumferentially along the side of the electrode body 21 away from the tab 32. That is, the protrusion 11 has a ring structure; specifically, both the connecting edge 112 and the folded edge 111 have a ring structure. With this arrangement, the folded edge 111 can completely limit the electrode body 21 circumferentially, and the limiting effect of the protrusion 11 on the electrode body 21 is better, which can further reduce the vibration of the electrode body 21, thereby further reducing the force transmitted to the tab 32 and further reducing the risk of the tab 32 tearing. Furthermore, in this embodiment, a, b, and c satisfy 0.12≤b×a / c≤12, which can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several layers of tab layers 321, reduce welding heat, and reduce the porosity formed during the welding process.

[0176] Or, in another embodiment, such as Figure 40As shown, the folded edge 111 is segmented along the circumference of the side of the electrode body 21 away from the tab 32. That is, the connecting edge 112 has a ring structure, and the folded edge 111 has a segmented structure, meaning that the folded edge 111 is discontinuous along the circumference. In this case, the heat dissipation effect of the electrode body 21 is better. However, the folded edge 111 limits part of the electrode body 21, making the limiting effect of the protrusion 11 on the electrode body 21 relatively poor. This will increase the vibration of the electrode body 21, causing the force on the tab 32 to increase, and the risk of the tab 32 tearing will increase relatively. Therefore, in this embodiment, a, b, and c are made to satisfy 0.13≤b×a / c≤13, which further reduces the porosity formed by the vaporization of manganese and / or silicon elements during the welding process, and can ensure the structural strength and shrinkage resistance of the tab layer 321, reduce the porosity generated at the junction of the first solder area 4 and the non-welded area, and reduce the risk of the tab 32 breaking when the battery is subjected to vibration.

[0177] It is worth noting that, please refer to Figure 38 and Figure 41 The outer casing 1 includes a housing 12 and a cover plate 13. At least one end of the housing 12 has an opening. The cover plate 13 is connected to the housing 12 and seals the opening to isolate the interior and exterior spaces of the housing 12. The cover plate 13 and the housing 12 are fixedly connected by welding, riveting, or bonding. Furthermore, the pole body 21 can be disposed on the housing 12 or on the cover plate 13. Furthermore, the housing 12 can be made of metals or alloys such as aluminum, aluminum alloy, steel, titanium, copper, or magnesium.

[0178] It should be noted that the main body can be either the housing 12 or the cover plate 13. That is, the protrusion 11 can be provided on the housing 12 (see [reference]). Figure 41 It can also be set in cover plate 13 (see Figure 37 and Figure 38 ).

[0179] In one embodiment, such as Figure 42 , Figures 57 to 60As shown, the adapter piece 22 is disposed between the outer casing and the cell body 31. The side of the adapter piece 22 away from the cell body 31 forms a welding surface 223. At least a portion of the tab portion 32 is folded to the welding surface 223 and welded to the welding surface 223 to form a first solder mark area 4. The terminal body 21 is welded to the welding surface 223. a, b, and c satisfy 0.005≤b×a / c≤12. In this embodiment, it is necessary to fold the first end of the tab portion 32 to the side of the adapter piece 22 away from the cell body 31, and then weld the tab portion 32 to the side of the adapter piece 22 away from the cell body 31, which can improve the utilization rate of the battery height space. However, during the cooling process of the first solder area 4, the tensile force applied by the cell body 31 to the tab 32 on the side of the first solder area 4 closest to the cell body 31 is relatively large. When the first solder area 4 shrinks and deforms, large pores are formed between the first solder area 4 and the non-welded area, increasing the risk of tab 32 breakage. Furthermore, in this case, the tab 32 is closer to the electrode body 21, making it easier for the force on the electrode body 21 to be transmitted to the tab 32, which also increases the risk of tab 32 breakage. Therefore, in this embodiment, by further limiting the range of b×a / c, the pores formed by the vaporization of manganese and / or silicon elements during the welding process are further reduced, and the structural strength and shrinkage resistance of the tab layer 321 can be guaranteed, reducing the pores generated at the junction of the first solder area 4 and the non-welded area, and reducing the risk of tab 32 breakage when the battery is subjected to vibration.

[0180] Furthermore, such as Figure 42 As shown, the tab portion is folded from the first edge 224 of the adapter piece 22 to the welding surface. Along the x-direction, the distance between the tab portion 32 and the first edge 224 is l2, satisfying 0.2mm≤l2≤3mm. This configuration ensures the welding quality between the terminal body 21 and the adapter piece 22, as well as the current carrying capacity between the terminal body 21 and the adapter piece 22, while preventing the tab portion 32 from overlapping with the battery casing 1 and causing a short circuit.

[0181] It is worth noting that if the value of l2 is too large, the distance between the tab 32 and the first edge 224 of the adapter piece 22 will be too far, resulting in redundant length of the tab 32 at the first edge 224. This will make it easier for the side of the tab 32 away from the first edge 224 to overlap with the battery casing 1, causing a short circuit in the battery. Furthermore, it will also cause the length of the tab 32 folded to the welding surface 223 to be too short, which will easily lead to the area used for welding the tab 32 and the adapter piece 22 being too small, affecting the current carrying capacity between the tab 32 and the adapter piece 22. If the value of l2 is too small, the distance between the tab 32 and the first edge 224 of the adapter plate 22 will be too close. When the tab 32 is bent at the first edge 224, the length of the tab 32 that can be accommodated will be short. Therefore, the length of the tab 32 folded onto the welding surface 223 will be longer, resulting in the end of the tab 32 being closer to the pole body 21. This makes it easier for the end of the tab 32 to overlap with the pole body 21, and the end of the tab 32 to be easily inserted between the pole body 21 and the adapter plate 22. This can lead to poor welding quality between the pole body 21 and the adapter plate 22, which in turn affects the current carrying capacity between the pole body 21 and the adapter plate 22. Furthermore, the tab 32 is more likely to tighten when bent at the first edge 224, which can easily lead to tearing of the tab 32 and affect the current carrying capacity of the tab 32.

[0182] Optionally, l2 can be any value from 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, or a value between any two of these values.

[0183] In one embodiment, such as Figure 43 , Figure 75 and Figure 76 As shown, the battery is a cylindrical battery. The cell 3 includes electrode sheets 33, which are wound to form several winding layers. Along the winding direction, each winding layer includes several tab layers 321. Along the winding direction, the width of the tab layer 321 is t1, satisfying 2mm≤t1≤10mm and 0.05≤b×a / c≤10. It is worth noting that for the small tab design of the cylindrical battery, compared with the welding of the large flat tab portion 32, there is a gap between the small tabs, which increases the risk of producing pores during the welding process, and thus increases the risk of breakage of the tab portion 32. Therefore, in this embodiment, by further limiting the value range of b×a / c, the pores formed by the vaporization of manganese and / or silicon elements during the welding process are further reduced, and the structural strength and shrinkage resistance of the tab layer 321 can be guaranteed, reducing the pores generated at the junction of the first solder area 4 and the non-welded area, and reducing the risk of breakage of the tab portion 32 when the battery is subjected to vibration.

[0184] Optionally, t1 can be any value from 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, or a value between any two of these values.

[0185] In one embodiment, such as Figure 75 and Figure 76 As shown, the battery is a cylindrical battery, with the diameter D of the cell body 31 not exceeding 50mm. The cell 3 also includes a second tab, which has opposite polarities to the tab 32. The second tab and the tab 32 extend from the cell body 31 along the same side of the axial direction, and a, b, and c satisfy 0.05≤b×a / c≤8. It is worth noting that when the diameter of the cell body 31 is small, the welding area between the tab 32 and the terminal assembly 2 will also be small, meaning that the current carrying capacity between the tab 32 and the terminal assembly 2 is inherently small. If a breakage occurs in the tab 32, it will have a significant impact on the current carrying capacity of the tab 32 and the terminal assembly 2. Therefore, in this embodiment, by further limiting the range of b×a / c, the porosity formed by the vaporization of manganese and / or silicon during the welding process is further reduced, and the structural strength and shrinkage resistance of the tab layer 321 can be guaranteed, the porosity generated at the junction of the first solder area 4 and the non-welded area is reduced, and the risk of breakage of the tab 32 when the battery is subjected to vibration is reduced.

[0186] Optionally, the value of D can be any value among 10mm, 20mm, 30mm, 40mm, and 50mm, or a value between any two of these values.

[0187] In another embodiment, the battery is a cylindrical battery, and the cell 3 further includes a second tab. The second tab and the tab 32 have opposite polarities and extend from opposite sides of the cell body 31 along the axial direction. This arrangement allows for a larger welding area between the tab 32 and the terminal assembly 2, thereby improving the current-carrying capacity between them. Therefore, the impact on the current-carrying capacity is smaller when the tab 32 breaks. Thus, in this embodiment, ensuring that a, b, and c satisfy 0.07 ≤ b × a / c ≤ 10 further improves the structural strength of the electrode 33, reduces the risk of lithium plating in the battery, and facilitates the welding of multiple tab layers 321, reducing welding heat and porosity formed during the welding process.

[0188] Furthermore, in this embodiment, the second tab and / or the tab 32 are arranged circumferentially along the winding direction. That is, the tabs of the cylindrical battery are of the full tab type, which allows for a larger welding area between the tab 32 and the terminal assembly 2, thereby further improving the current carrying capacity between the tab 32 and the terminal assembly 2. Therefore, the impact on the current carrying capacity is smaller when the tab 32 is dissected. Therefore, further, by ensuring that a, b, and c satisfy 0.1≤b×a / c≤6.5, the structural strength of the electrode 33 can be further improved, the risk of lithium plating in the battery can be reduced, and the welding of several tab layers 321 can be facilitated, reducing welding heat and reducing porosity formed during the welding process.

[0189] It is worth noting that the tab 32 serves as the positive tab of the battery cell 3, and the second tab serves as the negative tab of the battery cell 3.

[0190] In one embodiment, such as Figure 44 As shown, the tab layer 321 includes a polymer layer 3214 and conductive layers 3215 disposed on opposite sides of the polymer layer, where a, b and c satisfy 0.03≤b×a / c≤9.5.

[0191] Specifically, such as Figure 45 As shown, the battery cell 3 includes several layers of electrode sheets 33 stacked along the z-direction. Each electrode sheet 33 includes a current collector 3111 and an active material layer disposed on at least one side of the current collector 3111 along the z-direction. Part of the current collector 3111 and the active material layer form a sheet 311, and part of the current collector 3111 extends to form a tab layer 321. The several sheets 311 form the battery cell body 31, and the several tab layers 321 form a tab portion 32. The current collector 3111 includes a polymer layer 3214 and two conductive layers 3215 to form a composite current collector 3111. This improves the flexibility of the current collector 3111, reduces the risk of breakage of the tab portion 32, and reduces the risk of lithium plating caused by the expansion of the electrode sheets 33 during charging and discharging. Therefore, in this embodiment, by further limiting the range of values ​​for b×a / c, the structural strength of the electrode 33 can be further improved, the risk of lithium plating in the battery can be reduced, and the welding of several layers of tab layers 321 can be made easier, reducing welding heat and reducing pores formed during the welding process.

[0192] It is worth noting that the materials of polymer layer 3214 include polyamide (PA), polyterephthalate, polyimide (PI), polyethylene (PE), polypropylene (PP), polystyrene (PPE), polyvinyl chloride (PVC), aramid, acrylonitrile-butadiene-styrene copolymer (ABS), polybutylene terephthalate (PET), poly(p-phenylene terephthalamide) (PPTA), polypropylene (PPE), polyoxymethylene (POM), epoxy resin, phenolic resin, polytetrafluoroethylene (PTEE), polyvinylidene fluoride (PVDF), silicone rubber, polycarbonate (PC), polyvinyl alcohol (PVA), and polyethylene glycol (PEG). The conductive layer may contain at least one of the following: cellulose, starch, protein, derivatives of the above materials, cross-linked products of the above materials, and copolymers of the above materials; the conductive layer may contain aluminum, copper, nickel, etc.

[0193] Furthermore, in this embodiment, as Figure 44 As shown, along the z-direction, the thickness of the polymer layer 3214 is v1, and the thickness of the conductive layer 3215 is v2, satisfying 0.1≤v1 / v2≤0.8. This configuration improves the flexibility of the current collector 3111 while ensuring its conductivity.

[0194] It is worth noting that if v1 / v2 is too large, the thickness of the conductive layer 3215 will be small, which is not conducive to electron transmission, increases battery impedance, and increases battery voltage drop; if v1 / v2 is too small, the thickness of the polymer layer 3214 will be small, and the effect of improving the flexibility of the current collector 3111 will not be obvious, and there will still be a risk of delamination at the tab 32.

[0195] Optionally, v1 / v2 can be any value from 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, or a value between any two values.

[0196] In one embodiment, the battery cell 3 includes a plurality of electrode layers 33 stacked along the z-direction. Each electrode layer 33 includes a sheet body 311 and a tab layer 321 extending from at least one end of the sheet body 311. The plurality of sheet bodies 311 form the battery cell body 31, and the plurality of tab layers 321 form the tab portion 32. Figure 45As shown, the sheet 311 includes a current collector 3111 and an active material layer 3112 connected along the z-direction. The thickness of the active material layer 3112 along the z-direction is w, satisfying w ≥ 70 μm and 0.02% ≤ a% ≤ 1%. If the thickness of the active material layer 3112 is large, the electrode 33 will expand significantly during charging and discharging, increasing the risk of the current collector 3111 breaking and causing lithium plating. Therefore, in this embodiment, by limiting the range of a%, the structural strength of the current collector 3111 is further improved, reducing the risk of breakage and thus lowering the risk of lithium plating in the battery.

[0197] It is worth noting that the thickness w of the active material layer 3112 is the total thickness of the active material layer 3112 of the sheet 311. When the active material layer 3112 is disposed on one side of the current collector 3111, w is the thickness of one active material layer 3112; please refer to [link to relevant documentation]. Figure 45 When the active material layer 3112 is disposed on opposite sides of the current collector 3111, w is the sum of the thicknesses of the two active material layers 3112, that is, w = w1 + w2.

[0198] Optionally, w can be any value among 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, and 150μm, or a value between any two values. Of course, it can also be a value greater than 150μm.

[0199] It should be noted that the tab, as a key component of the battery, is used to transmit the internal current of the cell and lead the internal current out. The material of the tab can be the same as that of the current collector. For example, the tab can be made of at least one of the following: silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon, or titanium. Furthermore, the tab can be cut from the current collector or it can be a separately formed metal part. It can be understood that the positive tab is electrically connected to the positive electrode plate in the cell body, and the negative tab is electrically connected to the negative electrode plate in the cell body.

[0200] In one embodiment, such as Figure 46 As shown, the area of ​​the solder area of ​​the tab 32 and the terminal assembly 2 projected along the z-direction is S1, and the area of ​​the tab 32 projected along the z-direction is S2, satisfying 0.02≤S1 / S2≤0.4. This configuration improves the current flow capacity between the tab 32 and the terminal assembly 2 while reducing the risk of porosity generated during welding.

[0201] It is worth noting that if the value of S1 / S2 is too large, the distance between the solder area and the edge of the tab 32 may be too close, increasing the risk of porosity in the solder area. If the value of S1 / S2 is too small, the current flow area between the tab 32 and the terminal assembly 2 will be too small, resulting in insufficient current flow capacity.

[0202] It should be noted that you should refer to [link / reference]. Figure 46 If the tab 32 and the pole post assembly 2 are welded together only through the first sub-soldering area 10, then S1 is the orthogonal projection area of ​​the first sub-soldering area 10 along the z-direction; if the tab 32 and the pole post assembly 2 are welded together through the first sub-soldering area 10 and the second sub-soldering area 5, then S1 is the sum of the orthogonal projection area of ​​the first sub-soldering area 10 along the z-direction and the orthogonal projection area of ​​the second sub-soldering area 5 along the z-direction; if the tab 32 and the pole post assembly 2 are welded together through the first sub-soldering area 10 and the third sub-soldering area 5... If the sub-welding area 6 is welded, then S1 is the sum of the orthogonal projection area of ​​the first sub-welding area 10 along the z direction and the orthogonal projection area of ​​the third sub-welding area 6 along the z direction; if the electrode ear 32 and the electrode post assembly 2 are welded together through the first sub-welding area 10, the second sub-welding area 5 and the third sub-welding area 6, then S1 is the sum of the orthogonal projection area of ​​the first sub-welding area 10 along the z direction, the orthogonal projection area of ​​the second sub-welding area 5 along the z direction and the orthogonal projection area of ​​the third sub-welding area 6 along the z direction.

[0203] Optionally, the value of S1 / S2 can be any one of 0.02, 0.05, 0.1, 0.12, 0.15, 0.2, 0.22, 0.25, 0.3, 0.32, 0.35, or 0.4, or a value between any two values.

[0204] In one embodiment, such as Figure 47 As shown, the first solder mark area 4 includes multiple solder lines 9, which are intermittently arranged. That is, segmented welding is used when forming the solder mark area. It is worth noting that during the welding process of the multilayer tab layer 321, segmented welding is more efficient than continuous welding (forming...) Figure 48 As shown in the continuous weld line 9, segmented welding can reduce cracks and delamination caused by uneven thermal stress and excessively rapid cooling by effectively controlling heat input and cooling rate. Therefore, in this embodiment, making a, b, and c satisfy 0.06≤b×a / c≤11 can further improve the structural strength of the electrode 33, reduce the risk of lithium plating in the battery, and also facilitate the welding of several layers of tab layers 321, reduce welding heat, and reduce the porosity formed during the welding process.

[0205] It should be noted that when the solder areas (any one or more of the first sub-soldering area, the second sub-soldering area 5, and the third sub-soldering area 6) are formed by laser welding, segmented welding can be used.

[0206] In one embodiment, the outer shell 1 is made of aluminum and contains manganese and / or silicon, with the mass percentage of manganese and / or silicon ranging from 0.01% to 1.2%. It is worth noting that aluminum shells have relatively low structural strength and a higher risk of deformation. If the outer shell 1 deforms significantly, the electrode body 21 will experience greater stress, which in turn will cause greater stress on the electrode tab 32, increasing the risk of breakage. Therefore, in this embodiment, the mass percentage of manganese and / or silicon is controlled to improve the structural strength of the outer shell 1, reduce the risk of deformation, and thus reduce the risk of breakage of the electrode tab 32.

[0207] It should be noted that when the outer shell is made of aluminum, the material of the outer shell can be aluminum-manganese alloy, aluminum-magnesium alloy, etc. Optionally, the mass percentage of manganese and / or silicon can be any value from 0.01%, 0.05%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, or a value between any two of these.

[0208] In another embodiment, the outer shell 1 is made of steel and contains manganese and / or silicon, with the manganese and / or silicon accounting for 0.15% to 3% of the mass. It is worth noting that the steel shell has high structural strength, a low risk of deformation, and a small degree of deformation. Therefore, the stress on the pole body 21 is small, which reduces the stress on the pole tab 32 and thus reduces the risk of breakage of the pole tab 32.

[0209] It should be noted that when the outer shell is made of steel, the material can be stainless steel, carbon steel, nickel-plated steel, etc. Optionally, the mass percentage of manganese and / or silicon can be any one of 0.15%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%, or a value between any two of these.

[0210] It is worth noting that a battery cell is formed by stacking a positive electrode sheet, a negative electrode sheet, and a separator between them. The positive electrode sheet includes a positive current collector and a positive active material. The positive current collector can be made of metals such as aluminum foil, nickel foil, and stainless steel, or a composite foil formed by combining metals and insulating materials. The positive active material includes the main positive active material, a conductive agent, and a binder. The main positive active material includes one or more of the following lithium-containing positive active materials: lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate. Similarly, the negative electrode sheet includes a negative current collector and a negative active material. The negative current collector can be made of metals such as copper foil, aluminum foil, and stainless steel, or a composite foil formed by combining metals and insulating materials. The negative active material includes the main negative active material, a conductive agent, and a binder. The main negative active material includes one or more of the following negative active materials: artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0211] It is worth noting that the x-direction is the length direction of the tab 32, which is the direction in which the tab extends from the electrode plate 33, the y-direction is the width direction of the tab 32, and the z-direction is the thickness direction of the tab 32.

[0212] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0213] The preparation of the example battery and the comparative battery includes the following steps: (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, it is cold-pressed and slit to obtain the positive electrode sheet. Specifically, the mass ratio of positive electrode material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0214] (2) Preparation of negative electrode: The negative electrode active material graphite, conductive agent acetylene black, thickener CMC, and binder SBR are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained. The ratio of negative electrode graphite: conductive agent: thickener: binder is (90~96): (4~2): (2~1): (4~1).

[0215] (3) Preparation of electrolyte: Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0216] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0217] (5) Preparation of lithium-ion batteries: The above-mentioned positive electrode sheet, separator, and negative electrode sheet are stacked in sequence, and after winding or stacking, a bare cell is obtained; the bare cell is placed in the casing, dried, injected with electrolyte, and then packaged, left to stand, formed, and calibrated to obtain a lithium-ion battery.

[0218] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt and manganese, and lithium manganese iron phosphate. The negative electrode active material can be selected from one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0219] In this application, the positive electrode active material is selected from lithium iron phosphate as an example, and the mass ratio of positive electrode material: conductive agent: binder satisfies 96:2:2; the negative electrode material is selected from artificial graphite. Optionally, in other embodiments, the positive electrode material can be selected from one or more of nickel-cobalt-manganese ternary materials and lithium manganese iron phosphate; the negative electrode can also include one or more of silicon-carbon negative electrode or natural graphite.

[0220] The difference between the batteries in each embodiment and the comparative battery lies in the values ​​of a, b, and c, as shown in Table 1.

[0221] The relevant performance of the batteries in the above embodiments and comparative examples was tested, and the test results are recorded in Table 1. The test methods are as follows: 1. Battery vibration resistance test (1) Charge the batteries in the battery pack according to the preset method and adjust the charge of each battery in the battery pack to 50% SOC.

[0222] (2) Vibration test of the battery was carried out in accordance with the national standard GB 38031-2020, and the vibration parameters were tested in accordance with the requirements of GB 38031-8.2.1.

[0223] Next, 100 batteries from the battery pack were selected, and the voltage of each battery was tested. The maximum and minimum battery voltages were recorded, and the difference between the maximum and minimum values ​​was calculated. When the difference between the maximum and minimum values ​​was greater than 30mV, the battery voltage consistency within the battery pack was poor, and the pack was deemed unqualified.

[0224] 2. Lithium plating on the negative electrode At room temperature (25°C), the battery was charged at a constant current of 1C to 3.65V, then charged at a constant voltage until the cutoff current was less than or equal to 0.05C, and then discharged at 1C to 2.5V, for 800 cycles. Afterwards, the example battery and the comparative battery were charged at 1C to the upper limit voltage of 3.65V and the cutoff current of 0.05C, respectively, to obtain batteries at 100% SOC. The batteries were then disassembled in a dry environment to observe the lithium plating on the negative electrode. After disassembly, the lithium plating area / total negative electrode area ratio was greater than 20%, indicating severe lithium plating.

[0225] Table 1:

[0226] Based on Examples 1 to 17 and Comparative Examples 1 to 3, it can be seen that when the value of b×a / c is within the range of 0.004 to 15, the voltage difference between the batteries in the battery pack is no greater than 25mV, the voltage consistency of the batteries in the battery pack is good, the battery stability is good, and the proportion of lithium plating area is no greater than 4%, making the battery less prone to lithium plating problems. However, in Comparative Example 1, the value of b×a / c is not within the range of 0.004 to 15 and is less than 0.004, resulting in a voltage difference between the batteries in the battery pack greater than 30mV and a lithium plating area greater than 20%, making the battery unusable. In Comparative Examples 2 and 3, the value of b×a / c is not within the range of 0.004 to 15 and is greater than 15, resulting in a voltage difference between the batteries in the battery pack greater than 30mV and a lithium plating area greater than 5% and less than or equal to 6%, poor voltage consistency between the batteries in the battery pack, causing the battery to become unusable subsequently.

[0227] As can be seen from Examples 1 to 6, when the value of b×a / c is in the range of 0.2 to 7.5, the value of a% is in the range of 0.2% to 0.9%, the value of b is in the range of 0.01mΩ to 0.08mΩ, and the value of c is in the range of 0.008mm to 0.02mm, the voltage difference of the batteries in the battery pack is not greater than 5mV, and the batteries do not have lithium plating problems.

[0228] As can be seen from Example 14, although the value of b×a / c is in the range of 0.004 to 15, the value of a% is not in the range of 0.01% to 1.2% and is greater than 1.2%, and the value of b is not in the range of 0.008mΩ to 0.1mΩ and is greater than 0.1mΩ, resulting in a voltage difference of more than 20mV and less than 25mV in the battery pack.

[0229] As can be seen from Example 15, although the value of b×a / c is in the range of 0.004 to 15, the value of a% is not in the range of 0.01% to 1.2% and is less than 0.01%, and the value of c is not in the range of 0.006mm to 0.025mm and is less than 0.006mm, which leads to lithium plating problem in the battery, and the lithium plating area is greater than 3% and less than or equal to 4%.

[0230] According to an embodiment of the present invention, in another aspect, a battery pack 100 is also provided, such as... Figure 77 As shown, the device includes the battery 110 mentioned above, as well as a base plate and a frame. The frame is arranged around the outer periphery of the base plate, and the base plate and the frame are fixedly connected. The base plate and the frame together form an accommodating space, in which the battery is placed and fixedly connected to the base plate.

[0231] When the battery pack is subjected to vibration, voltage fluctuations within the battery pack should be avoided, as should large voltage differences between batteries. This is to prevent issues such as overcharging or undercharging of some batteries during charging and discharging, thus ensuring the overall consistency of the batteries during charging and discharging, thereby guaranteeing the battery's cycle life and preventing thermal runaway caused by heat accumulation in some batteries, thus ensuring the safety performance of the battery pack.

[0232] According to an embodiment of the present invention, in another aspect, an electrical appliance 1000 is also provided, such as... Figure 78 As shown, it includes the aforementioned battery pack 100. Specifically, the electrical device 1000 can be a vehicle.

[0233] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery, characterized in that, include: Outer shell (1); The pole assembly (2) is disposed on the outer casing (1); A battery cell (3) is disposed within the housing (1). The battery cell (3) includes a battery cell body (31) and a tab (32) extending from at least one end of the battery cell body (31). The tab (32) is welded to the terminal assembly (2) to form a first solder area (4). The tab (32) includes several stacked tab layers (321). The housing (1) has a lead-out through hole (14). The terminal assembly (2) is at least partially disposed in the lead-out through hole (14). The tab (32) is at least partially located within the lead-out through hole (14). The tab (32) contains aluminum, manganese and / or silicon, and the mass percentage of aluminum in a single tab layer (321) is not less than 96%, and the mass percentage of manganese and / or silicon is a%; A resistance test point is formed on the non-welded area of ​​the electrode (32), the first solder area (4) is located between the electrode assembly (2) and the resistance test point, and the resistance between the electrode assembly (2) and the resistance test point is b, where b is in mΩ. The thickness of the tab layer (321) is c, where c is in mm; a, b, and c satisfy the following conditions: 0.006 ≤ b × a / c ≤ 12.5, 0.01% ≤ a% ≤ 1.2%, 0.008 mΩ ≤ b mΩ ≤ 0.1 mΩ, and 0.006 mm ≤ c mm ≤ 0.025 mm.

2. The battery according to claim 1, characterized in that, Along the y-direction, the distance e1 between one side edge of the tab (32) and the edge of the cell body (31) on the same side and the distance e2 between the other side edge of the tab (32) and the edge of the cell body (31) on the same side satisfy e1≠e2, and the value of c mm satisfies 0.008mm≤c mm≤0.025mm.

3. The battery according to claim 1, characterized in that, Along the y direction, the two sides of the tab (32) are flush with the two sides of the cell body (31), and the value of c mm satisfies 0.006mm≤c mm≤0.02mm.

4. The battery according to any one of claims 1 to 3, characterized in that, Along the y-direction, at least one edge of the first solder area (4) is spaced apart from the edge of the tab (32) located on the same side.

5. The battery according to claim 4, characterized in that, The thickness c mm of the tab layer (321) satisfies 0.008 mm ≤ c mm ≤ 0.024 mm.

6. The battery according to claim 1, characterized in that, The first solder mark area (4) includes a first sub-solder mark area (10) and a second sub-solder mark area (5). Along the y direction, the second sub-solder mark area (5) is spaced apart from the first sub-solder mark area.

7. The battery according to claim 6, characterized in that, Along the y-direction, the distance between the first sub-soldering area (10) and the second sub-soldering area (5) is i2, which satisfies 2mm≤i2≤30mm.

8. The battery according to claim 1, characterized in that... The first solder area (4) includes a first sub-solder area (10) and a second sub-solder area (5). Along the y direction, the orthographic projection of the first sub-solder area (10) on the surface of the tab (32) is located within the orthographic projection of the second sub-solder area (5) on the surface of the tab (32).

9. The battery according to any one of claims 6 to 8, characterized in that, The first sub-soldering area (10) welds the tab (32) and the pole assembly (2), and the second sub-soldering area (5) welds the tab (32) and the pole assembly (2).

10. The battery according to any one of claims 6 to 8, characterized in that, The first sub-soldering area (10) welds the tab (32) and the pole assembly (2), and the second sub-soldering area (5) welds the tab (32) so that the multiple tab layers (321) are welded together.

11. The battery according to claim 1, characterized in that, The first solder mark area (4) includes a first sub-solder mark area (10) and a third sub-solder mark area (6), and the first sub-solder mark area (10) and the third sub-solder mark area (6) are spaced apart along the x direction.

12. The battery according to claim 1, characterized in that, The first solder area (4) includes a first sub-solder area (10) and a third sub-solder area (6). Along the x-direction, the orthographic projection of the first sub-solder area (10) on the surface of the tab (32) is located within the orthographic projection of the third sub-solder area (6) on the surface of the tab (32).

13. The battery according to claim 1, characterized in that, The pole assembly (2) includes a pole body (21), which is directly welded to the tab (32).

14. The battery according to claim 1, characterized in that, The pole assembly (2) includes a pole body (21) and an adapter plate (22), the pole body (21) and the adapter plate (22) are welded together, and the adapter plate (22) and the tab (32) are welded together.

15. The battery according to any one of claims 1 to 3, characterized in that, The battery cell (3) includes a plurality of electrode sheets (33) stacked along the z direction. Each electrode sheet (33) includes a sheet body (311) and a tab layer (321) extending from at least one end of the sheet body (311). The plurality of sheet bodies (311) form the battery cell body (31), and the plurality of tab layers (321) form the tab portion (32). The sheet (311) includes a current collector (3111) and an active material layer (3112) connected along the z direction. The thickness of the active material layer (3112) along the z direction is w, which satisfies w≥70μm and 0.02%≤a%≤1%.

16. The battery according to any one of claims 1 to 3, characterized in that, The area of ​​the solder area of ​​the tab (32) and the pole post assembly (2) along the z direction is S1, and the area of ​​the tab (32) along the z direction is S2, satisfying 0.02≤S1 / S2≤0.

4.

17. The battery according to any one of claims 1 to 3, characterized in that, The first solder area (4) includes multiple solder lines (9), which are intermittently arranged.

18. The battery according to any one of claims 1 to 3, characterized in that, The mass percentage of manganese is 0.005% to 0.2%; and / or, The mass percentage of silicon is 0.01% to 1%.

19. A battery pack, characterized in that, The battery (110) according to any one of claims 1 to 18 further includes a base plate and a frame, the frame being disposed around the outer periphery of the base plate, the base plate and the frame being fixedly connected, the base plate and the frame enclosing a receiving space, the battery being disposed within the receiving space and fixedly connected to the base plate.

20. An electrical appliance, characterized in that, Includes the battery pack (100) as described in claim 19.

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