Cylindrical battery

Abstract

The utility model provides a kind of cylindrical battery, comprising: shell pole, pole is led out from one end of shell;Electric core is arranged in shell, electric core leads out there is first tab and second tab, the polarity of first tab and second tab is opposite, first tab is connected with shell, to make shell form first current output end, second tab is welded with pole connection, and welding mark is formed on second tab, to make pole form second current output end;Insulating structure includes insulating layer and glue layer being arranged on insulating layer, insulating structure forms non-adhesion area in the area outside glue layer, at least part of glue layer is adhered on the circumference of electric core, non-adhesion area extends to the surface of second tab.The coincidence size between the scheme optimization non-adhesion area and second tab, the adhesion size of glue layer on electric core, and the size between non-adhesion area and welding mark, can take into account the heat dissipation effect of second tab and the warping risk of non-adhesion area.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, specifically to cylindrical batteries. Background Technology

[0002] In a cylindrical battery, the central terminal serves as one input / output terminal, and the casing serves as the other. The first tab of the cell is electrically connected to the terminal, and the second tab is electrically connected to the casing. One of the first and second tabs is the positive tab, and the other is the negative tab. During use, there is a risk of contact between the tabs and the casing (which has opposite polarity). This can easily cause a short circuit inside the battery, leading to thermal runaway and affecting the overall safety of the battery. Utility Model Content

[0003] In view of this, the present invention provides a cylindrical battery to solve the problems of the tabs of the existing cylindrical batteries being easily torn by the tape and having poor heat dissipation.

[0004] This utility model provides a cylindrical battery, comprising: a casing; terminals disposed on a first end face of the casing; a cell disposed inside the casing, including a second end face and a peripheral face, wherein a first tab and a second tab are led out from the second peripheral face of the cell, the first tab and the second tab having opposite polarities, the first tab being electrically connected to the casing to form a first current output terminal, the second tab being electrically connected to the terminals, and a solder mark being formed on the second tab to form a second current output terminal; and an insulating structure including an insulating layer and an adhesive layer disposed on the insulating layer. The insulating structure forms a non-adhesive region outside the adhesive layer. At least a portion of the adhesive layer is adhered to the circumferential surface of the cell. The non-adhesive region extends to the surface of the second electrode lug. In the radial direction of the cell, the dimension of the overlapping portion of the non-adhesive region and the second electrode lug is L1. In the axial direction of the cell, the adhesion dimension of the adhesive layer on the circumferential surface of the cell is L2. In the radial direction of the cell, the minimum dimension from the end of the insulating structure to the solder mark is L3, 0.9mm≤(L1×L2) / L3≤260mm, where L1 is in mm, L2 is in mm, and L3 is in mm.

[0005] Beneficial effects The technical solution of this utility model includes an adhesive layer and a non-adhesive area in its insulating structure. By extending the non-adhesive area to the surface of the second electrode tab, the insulating structure can provide insulation and protection for the second electrode tab without pulling it. This prevents the insulating layer on the end face of the cell from folding outward and pulling the electrode tab, causing it to overlap with the shell of opposite polarity, thus avoiding the risk of short circuit when the electrode tab overlaps with the shell. Furthermore, this solution optimizes the overlap dimensions between the non-adhesive area and the second electrode tab, the adhesion dimensions of the adhesive layer on the cell, and the dimensions between the non-adhesive area and the solder mark, thus balancing the heat dissipation effect of the second electrode tab and the risk of warping and detachment of the non-adhesive area. Therefore, this utility model solves the problems of the electrode tabs of existing cylindrical batteries being easily torn by adhesive tape and having poor heat dissipation. Attached Figure Description

[0006] To more clearly illustrate the specific embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0007] Figure 1 This is a schematic diagram of the structure of a cylindrical battery according to a first embodiment of the present invention; Figure 2 It shows Figure 1 Exploded view of a cylindrical battery; Figure 3 It shows Figure 1 A schematic diagram of the structure of a cylindrical battery cell; Figure 4 It shows Figure 1 A schematic diagram of the insulation structure of a cylindrical battery; Figure 5 It shows Figure 1 A schematic diagram showing the positional relationship between the cell, the second electrode tab (after being straightened), and the insulation structure of a cylindrical battery. Figure 6 It shows Figure 1 A schematic diagram showing the positional relationship between the cell, first tab, second tab, insulation structure, first current collector, second current collector, and terminal post of a cylindrical battery. Figure 7 It shows Figure 1 A schematic diagram of the electrode and separator structure of a medium cylindrical battery; Figure 8 It shows Figure 7 A schematic diagram of the structure at the tab of the intermediate electrode plate; Figure 9 It shows Figure 1 A schematic diagram of the insulation structure and single electrode tab of a cylindrical battery; Figure 10 This is a schematic diagram of the structure of a second embodiment of the cylindrical battery of this utility model.

[0008] Explanation of reference numerals in the attached figures: 10. Shell; 101. First end face; 20. Pole post; 30. Battery cell; 31. Electrode; 311. Tab layer; 32. Separator; 301. Second end face; 302. Peripheral surface; 303. Connecting section; 40. First pole ear; 50. Second pole ear; 51. Root; 52. Bend; 53. Single pole ear; 60. Solder mark; 70. Insulating structure; 71. Insulating layer; 72. Adhesive layer; 73. Non-adhesive area; 701. First end point; 702. Second end point; 80. First collection of components; 90. Second collection of components. Detailed Implementation

[0009] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0010] In a cylindrical battery, the central terminal serves as one input / output terminal, and the outer casing serves as the other. The first tab of the cell is electrically connected to the terminal, and the second tab is electrically connected to the outer casing. One of the first and second tabs is the positive tab, and the other is the negative tab. During use, the tabs may overlap with the casing (which has opposite polarity), creating a risk of short circuits and thermal runaway, thus compromising the overall safety of the battery.

[0011] Research has found that the reasons for the tabs overlapping with the casing, besides being due to the tabs being too close to the casing and the creepage distance between them being too short, causing a short circuit, also include the insulation layer on the outer periphery of the battery cell. This insulation layer, adhered to the outer periphery of the battery cell, can sometimes bend and fold outwards in a direction away from the center of the cell, i.e., the insulation layer springs back. During this springback, the adhesive layer of the insulation layer pulls on the adhered tabs, causing them to move outwards in the opposite direction. This outward folding of the tabs overlaps with the casing, making the battery more susceptible to short circuits and thermal runaway.

[0012] To address this technical problem, the applicant optimized the structure of the insulating tape, placing the adhesive layer only on the insulating portion of the tape, meaning a section of the tape lacks an adhesive layer, creating a non-adhesive area. During assembly, this non-adhesive area covers the first electrode tab. With this insulating tape structure, because the non-adhesive area lacks an adhesive layer, the first electrode tab is not pulled, thus preventing the tab from overlapping with the housing and causing a short circuit failure.

[0013] However, the applicant discovered the following further problems with the aforementioned insulating tape during use.

[0014] First, because the non-adhesive area lacks an adhesive layer for fixation, it is prone to warping and detaching from the surface of the tab, leading to short circuits due to overlap between the tab and the housing. Second, even though the non-adhesive area covers the tab, it still affects heat dissipation.

[0015] To address the aforementioned technical problems, this application provides a cylindrical battery, as detailed below.

[0016] Example 1 like Figures 1 to 9 As shown, an embodiment of the cylindrical battery according to this application includes a casing 10, terminals 20, a cell 30, and an insulation structure 70.

[0017] like Figure 1 and Figure 2 As shown, the housing 10 is cylindrical and made of metal. The housing 10 has a first end face 101, and the pole piece 20 is disposed on the first end face 101 of the housing 10. Furthermore, an insulating element is disposed between the housing 10 and the pole piece 20, and the housing 10 and the pole piece 20 respectively form two input and output terminals.

[0018] The pole post 20 can be disposed on the outside of the first end face 101 of the housing 10, or the pole post 20 can extend out from the first end face 101 of the housing 10.

[0019] A battery cell 30 is disposed within a housing 10, and the battery cell 30 has a second end face 301 and a peripheral face 302. A first electrode tab 40 and a second electrode tab 50 are led out from the second end face 301 of the battery cell 30, and the polarities of the first electrode tab 40 and the second electrode tab 50 are opposite. The first electrode tab 40 is electrically connected to the housing 10, so that the housing 10 forms a first current output terminal. The second electrode tab 50 is electrically connected to a terminal post 20, and a solder mark 60 is formed on the second electrode tab 50, so that the terminal post 20 forms a second current output terminal.

[0020] Specifically, the battery cell 30 includes an electrode 31, and the electrode includes a tab layer 311. The electrode 31 includes a positive electrode and a negative electrode, and the battery cell is formed by stacking and winding positive electrode strip, separator strip, and negative electrode strip. The separator 32 is larger than the negative electrode, and the negative electrode is larger than the positive electrode. The positive tab of the positive electrode is folded together to form one of the first tab portion 40 and the second tab portion 50, and the negative tab of the negative electrode is folded together to form the other of the first tab portion 40 and the second tab portion 50.

[0021] Furthermore, the second electrode lug 50 is provided with a solder mark 60, which can be a pre-weld solder mark or a final solder mark. Pre-welding involves welding and fixing the loose electrode lug to form the second electrode lug 50, while final soldering involves welding the second electrode lug 50 to the adapter piece (i.e., the second current collector 90), thereby achieving an electrical connection between the second electrode lug 50 and the electrode post 20. Alternatively, final soldering can directly weld the second electrode lug 50 to the electrode post.

[0022] Furthermore, the electrical connection between the second electrode tab 50 and the electrode post 20 means that the second electrode tab 50 can be directly welded to the electrode post 20, or the second electrode tab 50 can be first welded to the adapter piece, and then the adapter piece can be welded to the second electrode post 20.

[0023] The insulating structure 70 includes an insulating layer 71 and an adhesive layer 72 disposed on the insulating layer 71. The insulating structure 70 forms a non-adhesive region 73 in the area outside the adhesive layer 72. At least a portion of the adhesive layer 72 is adhered to the peripheral surface of the cell 30, and the non-adhesive region 73 extends to the surface of the second electrode tab 50.

[0024] That is, after being bent, the non-adhesive area 73 covers at least part of the second electrode ear 50, thereby providing insulation and protection for the second electrode ear 50. At the same time, since the non-adhesive area 73 does not have an adhesive layer, the non-adhesive area 73 does not adhere to the second electrode ear 50.

[0025] Furthermore, the positional relationship between the battery cell 30, the second electrode tab 50, and the insulation structure 70 is as follows: Figure 5 As shown. It should be noted that, Figure 5 The second pole ear 50 is a schematic diagram after being straightened from a bent state. Therefore Figure 5The vertical direction of the second electrode tab 50 shown is actually the radial direction of the second electrode tab 50 along the cell 30.

[0026] In the radial direction of the cell 30, the dimension of the overlapping portion of the non-bonded area 73 and the second electrode tab 50 is L1. In the axial direction of the cell 30, the bonding dimension of the adhesive layer 72 on the circumferential surface of the cell 30 is L2. In the radial direction of the cell 30, the shortest distance from the insulation structure 70 to the solder mark 60 is L3. Furthermore, L1, L2, and L3 satisfy the following relationship: 0.9mm≤(L1×L2) / L3≤260mm.

[0027] The units for L1, L2, and L3 are mm.

[0028] L1 represents the size of the overlapping portion of the non-bonded area 73 and the second electrode tab 50 in the radial direction of the cell 30. Since the second electrode tab 50 is a high-heat-generating area, a larger L1 value results in a larger area of ​​the non-bonded area 73 covering the second electrode tab 50, which is detrimental to heat dissipation. However, with a larger L1 value, the risk of warping of the non-bonded area 73 is lower, reducing the risk of the non-bonded area 73 detaching from the second electrode tab 50 and causing a short circuit.

[0029] The smaller the value of L1, the smaller the area of ​​the non-bonded region 73 covering the second electrode ear 50, which is beneficial for heat dissipation of the second electrode ear 50. However, when the value of L1 is small, the risk of warping of the non-bonded region 73 is greater, which may cause the non-bonded region 73 to detach from the second electrode ear 50 and result in a short circuit.

[0030] Therefore, L1 should be chosen at a moderate value to balance the heat dissipation effect of the second electrode ear 50 and the risk of short circuit.

[0031] In this embodiment, L1 is in the range of 0.5 mm to 6 mm.

[0032] For example, the value of L1 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm or 6mm, etc., as well as any value between two values.

[0033] L2 represents the bonding dimension of the adhesive layer 72 on the circumferential surface of the cell 30 along its axial direction. A larger value for L2 results in a larger bonding area of ​​the adhesive layer 72 on the circumferential surface of the cell 30. This increases the area of ​​the thickened portion of the cell 30 by the adhesive layer 72 and is detrimental to the overall heat dissipation of the cell 30. However, when L1 is larger, the insulation structure 70 is firmly bonded, reducing the risk of warping in the non-bonded area 73 and thus the risk of the non-bonded area 73 detaching from the second electrode tab 50 and causing a short circuit.

[0034] The smaller the value of L2, the smaller the bonding area of ​​the adhesive layer 72 on the periphery of the cell 30, and the smaller the area of ​​the cell 30 thickened by the adhesive layer 72, which is beneficial to the overall heat dissipation of the cell 30. However, when the value of L2 is small, the bonding strength of the insulation structure 70 is relatively weak, and the risk of warping of the non-bonded area 73 is greater, which may cause the non-bonded area 73 to detach from the second electrode tab 50 and lead to a short circuit.

[0035] Therefore, L2 should be set to a moderate value to balance the heat dissipation effect of cell 30 and the risk of short circuit.

[0036] In this embodiment, L2 is in the range of 5mm to 25mm.

[0037] For example, the value of L2 can be 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, 17mm, 19mm, 21mm, 23mm or 25mm, etc., as well as any value between two values.

[0038] L3 represents the shortest distance from the end of the insulation structure 70 to the solder mark 60 in the radial direction of the cell 30, that is, the distance from the end of the non-bonded area 73 to the solder mark 60. The solder mark 60 is a current-carrying area, and therefore generates significant heat. The larger the value of L3, the farther the non-bonded area 73 is from the solder mark 60 where heat is generated, and the better the heat dissipation effect of the second electrode tab 50. However, when L3 is large, there is a larger area of ​​the second electrode tab 50 that is not protected by the non-bonded area 73, and the greater the risk of short circuit between the second electrode tab 50 and the housing 10.

[0039] Furthermore, in some embodiments not shown, the end of the insulation structure 70 in the radial direction of the cell 30 may also be an adhesive layer 72.

[0040] The smaller the value of L3, the closer the non-bonded area 73 is to the solder 60 that generates significant heat, and the worse the heat dissipation effect of the second electrode tab 50. However, when L3 is small, the area of ​​the second electrode tab 50 that is not protected by the non-bonded area 73 is smaller, and the risk of short circuit between the second electrode tab 50 and the housing 10 is lower.

[0041] Therefore, L3 should be chosen at a moderate value to balance the heat dissipation effect of the second electrode ear 50 and the risk of short circuit.

[0042] In this embodiment, L3 is in the range of 0.5 mm to 4 mm.

[0043] For example, the value of L3 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm or 4mm, etc., as well as any value between two values.

[0044] For the relationship (L1×L2) / L3, if the value is too small, it means that the proportions of the two parameters (L1×L2) are too small and the proportion of L3 is too large. In this case, the heat dissipation effect of the second electrode tab 50 is good, but the non-adhesive area 73 warps and the risk of detaching from the second electrode tab 50 increases. This makes it easy for the second electrode tab 50 to overlap with the housing 10, causing a short circuit. If the value is too large, the proportions of the two parameters L1×L2 are too large and the proportion of L3 is too small. In this case, the non-adhesive area 73 is less likely to warp and detach, the risk of the second electrode tab 50 overlapping with the housing 10 is reduced, and a short circuit is less likely. However, in this case, the heat dissipation effect of the second electrode tab 50 deteriorates.

[0045] For example, the value of (L1×L2) / L3 can be 0.9, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250 or 260, etc., as well as any value between the two values.

[0046] Furthermore, the applicant conducted relevant experiments on various parameters of the battery in this embodiment, as detailed below.

[0047] Battery manufacturing (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) are mixed, and methylpyrrolidone (NMP) solvent 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, dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the positive electrode sheet is obtained. Specifically, the mass ratio of positive electrode material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0048] (2) Preparation of negative electrode: The negative electrode active material graphite, conductive agent acetylene black, thickener carboxymethyl cellulose (CMC), and binder styrene-butadiene latex (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).

[0049] (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.

[0050] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0051] (5) Preparation of lithium-ion batteries: The above-mentioned positive electrode sheet, separator, and negative electrode sheet are stacked in sequence, wound to obtain a cylindrical bare battery cell, and an insulating structure is attached. The bare cell is placed in a cylindrical shell (the diameter of the cylindrical shell is 45mm and the height is 95mm), dried, injected with electrolyte, and then packaged, left to stand, formed, and volume-adjusted to obtain a lithium-ion battery. 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 negative electrode active materials, including artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0052] In this application, the positive electrode active material is selected from nickel-cobalt-manganese ternary LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode material: conductive agent: binder satisfies 96:2:2; the main material of negative electrode is selected from artificial graphite.

[0053] Battery testing 1. Insulation structure warpage ratio test: Following the battery preparation method described above, 200 lithium-ion cylindrical batteries were prepared for each embodiment and comparative example. The prepared lithium-ion cylindrical batteries were charged at room temperature (25°C) with a constant current of 0.33C to the upper limit voltage of 4.25V, then discharged at a constant voltage until the current dropped to 0.05C. After standing for 5 minutes, the batteries were discharged at a constant current of 0.33C to the lower limit voltage of 2.5V. This constituted one cycle.

[0054] After 200 cycles, disassemble the cylindrical battery casing and observe whether the insulation structure has warped. Record the total number of lithium-ion batteries with warped insulation and calculate the warping percentage. The calculation formula is: "Warping percentage = (Total number of lithium-ion batteries with warped insulation / 200) * 100%".

[0055] If the warping rate of the insulation structure is less than or equal to 5%, it is considered qualified; if it is greater than 5%, it is considered unqualified.

[0056] 2. Battery temperature rise rate test: Following the battery fabrication method described above, 20 lithium-ion cylindrical batteries were prepared for each embodiment and comparative example. After discharging the lithium-ion cylindrical batteries at a constant current of 0.33C to the lower limit voltage of 2.5V, they were allowed to stand for 60 minutes. After standing... Measure the temperature of the battery casing at this point and record it as t1. Then charge the lithium-ion battery at 1C to the upper limit voltage of 4.25V, record the time as T, and measure the temperature of the battery casing at this point and record it as t2. Calculate the temperature rise rate using the formula (temperature rise rate = (t2 - t1) / T), and take the average value as the temperature rise rate of the lithium-ion battery under this parameter. If the temperature rise rate is greater than or equal to 0.9°C / min, it is unqualified; if the temperature rise rate is less than 0.9°C / min, it is qualified.

[0057] The specific results of the test are as follows.

[0058]

[0059] As can be seen from the test results above, in Examples 1 to 11, since the value of (L1×L2) / L3 is within the preferred range, the warpage ratio and heating rate of each cylindrical battery in Examples 1 to 11 are within the qualified standard.

[0060] In Example 1, the value of L1 is relatively small and falls within the lower limit of the preferred range, which also makes the value of (L1×L2) / L3 fall within the lower limit of the preferred range. Therefore, the cylindrical battery in Example 1 has a relatively high short-circuit risk and a relatively high warpage ratio. However, the cylindrical battery in Example 1 has good heat dissipation performance and a relatively slow heating rate, which is lower than the acceptable standard for heating rate.

[0061] In Example 3, the value of L2 is relatively small and falls within the lower limit of the preferred range. Therefore, the cylindrical battery in Example 3 has a relatively high short-circuit risk and a relatively high warpage rate. However, the cylindrical battery in Example 3 has good heat dissipation performance and a relatively slow heating rate.

[0062] In Example 4, the value of L3 is relatively large and falls within the upper limit of the preferred range. Therefore, the cylindrical battery in Example 4 has a relatively high short-circuit risk and a relatively high warpage rate. However, the cylindrical battery in Example 4 has good heat dissipation performance and a relatively slow heating rate.

[0063] In Example 7, the value of L2 is relatively large and falls within the upper limit of the preferred range. Therefore, the cylindrical battery in Example 7 has poor heat dissipation and a relatively fast heating rate. However, the cylindrical battery in Example 7 has a relatively low short-circuit risk and a relatively low warpage rate.

[0064] In Example 8, the value of L3 is small and falls within the lower limit of the preferred range, while the value of (L1×L2) / L3 falls within the upper limit of the preferred range. Therefore, the cylindrical battery in Example 8 has poor heat dissipation and a relatively fast heating rate. However, the cylindrical battery in Example 8 has a relatively low short-circuit risk and a relatively low warpage rate.

[0065] In Example 9, the value of L1 is relatively large and falls within the upper limit of the preferred range. Therefore, the cylindrical battery in Example 9 has poor heat dissipation and a relatively fast heating rate. However, the cylindrical battery in Example 9 has a relatively low short-circuit risk and a relatively low warpage rate.

[0066] In Example 10, the value of L1 is relatively small and less than the lower limit of the preferred range. However, by adjusting the values ​​of L2 and L3, the value of (L1×L2) / L3 is still within the preferred range. However, because the value of L1 is small, the short-circuit risk of the cylindrical battery in Example 10 is relatively high, and the warpage ratio is at a relatively high level (near the pass standard). However, the heat dissipation performance of the cylindrical battery in Example 10 is good, and the heating rate is relatively slow.

[0067] In Example 11, the value of L3 is relatively small and less than the lower limit of the preferred range. However, by adjusting the values ​​of L1 and L2, the value of (L1×L2) / L3 remains within the preferred range. However, due to the small value of L3, the cylindrical battery in Example 11 has poor heat dissipation and a relatively fast heating rate (near the acceptable standard). However, the cylindrical battery in Example 11 has a relatively low short-circuit risk and a relatively low warpage rate (generally lower than other examples).

[0068] In Example 12, the value of L2 is relatively small and less than the lower limit of the preferred range. However, by adjusting the values ​​of L1 and L3, the value of (L1×L2) / L3 is still within the preferred range. However, because the value of L2 is small, the short-circuit risk of the cylindrical battery in Example 12 is relatively high, and the warpage ratio is at a relatively high level (near the pass standard). However, the heat dissipation performance of the cylindrical battery in Example 12 is good, and the heating rate is relatively slow.

[0069] In Comparative Example 1, the value of L3 is relatively large, exceeding the upper limit of the preferred range, and causing the value of (L1×L2) / L3 to be less than the lower limit of the preferred range. Therefore, the short-circuit risk of the cylindrical battery in Comparative Example 1 is relatively high, and the warpage ratio is at a relatively high level. Furthermore, based on the test results, the warpage ratio of the cylindrical battery in Comparative Example 1 is unqualified.

[0070] In Comparative Example 2, the value of L1 is relatively large, exceeding the upper limit of the preferred range, and causing the value of (L1×L2) / L3 to be greater than the lower limit of the preferred range. Therefore, the cylindrical battery in Comparative Example 2 has poor heat dissipation capacity and a relatively fast heating rate. Furthermore, the test results show that the heating rate of the cylindrical battery in Comparative Example 2 is unqualified.

[0071] In Comparative Example 3, the value of L2 is relatively small, exceeding the lower limit of the preferred range. Meanwhile, because the value of L1 is small and the value of L3 is large, the value of (L1×L2) / L3 is less than the lower limit of the preferred range. Therefore, the cylindrical battery in Comparative Example 3 has a relatively high short-circuit risk and a relatively high warpage rate. Furthermore, the test results show that the warpage rate of the cylindrical battery in Comparative Example 3 is unacceptable.

[0072] like Figure 3 and Figure 5 As shown, in the technical solution of this embodiment, a connecting segment 303 is formed between the second end face 301 and the peripheral face 302 of the battery cell 30, and the non-adhesive area 73 corresponds at least partially to the connecting segment 303.

[0073] Specifically, the connecting section 303 is the junction between the second end face 301 and the peripheral surface 302. By aligning at least a portion of the non-adhesive area 73 with the connecting section 303, the connection between the second end face 301 and the peripheral surface 302 of the cell 30 is prevented from being covered by the adhesive layer 72. If the adhesive layer 72 covers the connecting section 303, the insulation structure 70 will wrinkle, compressing the separator 32. This will cause stress concentration on the outer periphery of the separator 32 of the cell 30, resulting in wrinkling of the separator 32 and posing a risk of internal short circuit in the battery.

[0074] like Figure 3 and Figure 5 As shown, in the technical solution of this embodiment, the non-adhesive area 73 extends from the connecting section 303 to the second end face 301 of the battery cell 30.

[0075] Specifically, on the one hand, the non-adhesive area 73 can provide insulation protection for the second electrode lug 50 on the second end face 301. On the other hand, no adhesive layer 72 is provided on the non-adhesive area 73 to prevent the second electrode lug 50 from being torn or short-circuited due to being pulled.

[0076] like Figure 3 and Figure 5 As shown, in the technical solution of this embodiment, the insulation structure 70 includes a first end point 701 and a second end point 702. The first end point 701 is fixed on the peripheral surface 302 of the battery cell 30, and the second end point 702 and the second end surface 301 of the battery cell 30 are disposed opposite to each other.

[0077] Wherein, the first end point 701 of the insulating structure 70 refers to the end of the insulating structure 70 that is away from the second end face 301. The second end point 702 of the insulating structure 70 refers to the end of the insulating structure 70 that faces the second end face 301.

[0078] Furthermore, the second end point 702 of the insulating structure 70 is adhered to the second end face 301 of the battery cell 30. Simultaneously, the insulating structure 70 forms an adhesive layer 72 and a non-adhesive region 73. In some embodiments not shown, the insulating structure 70 may also form a structure of "adhesive layer 72 - non-adhesive region 73 - adhesive layer 72". That is, the second end point 702 can be either a non-adhesive region 73 or an adhesive layer 72.

[0079] like Figure 3 and Figure 5 As shown, in the technical solution of this embodiment, the adhesive layer 72 extends from the first end point 701, and the adhesive layer 72 is spaced apart from the second end face 301 of the battery cell 30.

[0080] In other words, in this embodiment, the adhesive layer 72 is not attached to the end of the peripheral surface 302 of the cell 30 (i.e., the connecting section 303), thereby preventing the outer peripheral separator 32 of the cell 30 from wrinkling and causing a short circuit in the positive and negative electrode plates.

[0081] like Figure 9 As shown, in the technical solution of this embodiment, the second electrode ear 50 and the edge of the second end face 301 of the battery cell 30 are spaced apart, and the spacing distance i is in the range of 0.2mm to 1.2mm.

[0082] Specifically, if the value of i is too small, the distance between the edge of the second tab 50 and the second end face 301 of the cell 30 will be too small, increasing the risk of the second tab 50 overlapping with the casing 10 and increasing the risk of internal short circuit failure of the battery. If the value of i is too large, the distance between the second tab 50 and the second end face 301 of the cell 30 will be too large. This will result in concentrated heat generation at the second tab 50 and a smaller current-carrying area, affecting the overall charging rate of the battery. Therefore, the value of i should be moderate.

[0083] For example, the value of i can be 0.2mm, 0.4mm, 0.6mm, 0.6mm, 1.0mm or 1.2mm, etc., or any value between two values.

[0084] like Figure 9 As shown, in the technical solution of this embodiment, the second electrode portion 50 includes a plurality of single electrode tabs 53. The dimension j of the single electrode tab 53 along its extension direction is greater than the edge spacing i between the second electrode portion 50 and the second end face 301 of the battery cell 30.

[0085] Specifically, the value of j should be controlled. If j is too large, the radial dimension of the second tab 50 will be too large, and the distance between the second tab 50 and the edge of the second end face 301 of the cell 30 will be too small. This increases the risk of the second tab 50 overlapping with the casing 10, and increases the risk of internal short circuit failure of the battery. If j is too small, the radial dimension of the second tab 50 will be too small. This will result in concentrated heat generation in the second tab 50, and the current-carrying area of ​​the second tab 50 will be small, affecting the overall charging rate of the battery.

[0086] like Figure 3 and Figure 9 As shown, in this embodiment, the insulating structure 70 is continuously disposed on the circumferential surface 302 of the battery cell 30. Furthermore, in this embodiment, the insulating structure 70 does not completely cover the battery cell 30 in the circumferential direction; that is, the two ends of the insulating structure 70 in the circumferential direction have a gap.

[0087] In this way, the insulation structure 70 can better achieve insulation protection for the battery cell 30, and prevent the second electrode ear 50 from overlapping with the shell 10 with opposite polarity.

[0088] like Figure 9 As shown, along the radial direction of the cell 30, the size k of the insulating layer 71 is in the range of 3 mm to 25 mm.

[0089] Specifically, a larger value for k makes the portion of the non-adhesive region 73 located on the second end face 301 less likely to fold outward, thus improving the insulation performance of the second end face 301 of the cell 30. However, if the value of k is too large, the area covered by the non-adhesive region 73 on the second electrode tab 50 will be larger, thereby affecting the current-carrying area and heat dissipation efficiency of the second electrode tab 50. Therefore, k should be chosen in a moderate value to balance the insulation performance of the cell 30, the current-carrying capacity of the second electrode tab 50, and the heat dissipation performance.

[0090] For example, the value of k can be 3mm, 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, 17mm, 19mm, 21mm, 23mm or 25mm, etc., as well as any value between two values.

[0091] like Figure 5 As shown, in the technical solution of this embodiment, the adhesive layer 72 does not overlap with the root 51 of the second electrode ear 50, and the distance a between the end of the adhesive layer 72 and the root 51 of the second electrode ear 50 is in the range of 0.5mm to 4mm.

[0092] Specifically, the root 51 of the second tab 50 refers to the boundary between the electrode 31 and the tab layer 311, whether or not an active material is coated thereon.

[0093] In this embodiment, the adhesive layer 72 does not cover the root 51 of the second electrode ear 50, and as... Figure 5 As shown, the upper edge of the adhesive layer 72 is located below the root 51 of the second electrode lug 50. This avoids pulling on the root 51, which could cause the second electrode lug 50 to tear. Regarding the value of 'a', if 'a' is too small, the second electrode lug 50 may be pulled; if 'a' is too large, the adhesive layer 72 will have a small bonding area, making the non-bonded area 73 prone to warping, potentially causing the second electrode lug 50 to overlap with the housing 10 and resulting in a short circuit.

[0094] For example, the value of 'a' can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, and 4mm, as well as any value between two values.

[0095] like Figure 5 and Figure 6 As shown, in the technical solution of this embodiment, the height of the battery cell 30 along the axial direction is H, and the ratio of L2 to H is in the range of 0.03 to 0.5. Specifically, if the ratio of L2 to H is too small, the area bonded by the adhesive layer 72 is small, and the non-bonded area 73 is prone to warping, causing the second electrode ear 50 to overlap with the housing 10 and resulting in a short circuit. If the ratio of L2 to H is too large, the area bonded by the adhesive layer 72 is large, and the area of ​​the battery cell 30 covered by the adhesive layer 72 is thicker, which is not conducive to the overall heat dissipation of the battery cell 30.

[0096] For example, the ratio of L2 to H can be 0.03, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5, etc., as well as any value between the two values.

[0097] Optionally, the height H of the cell 30 is in the range of 50mm to 200mm.

[0098] For example, the value of H can be 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm or 200mm, etc., as well as any value between two values.

[0099] like Figure 5 and Figure 6 As shown in the technical solution of this embodiment, the size of the second electrode ear 50 is b in the lead-out direction of the second electrode ear 50. The ratio of L1 to b is in the range of 0.1 to 0.8; It should be noted that the dimension 'b' of the second tab 50 does not mean the length of a single tab layer 311. Because the second tab 50 is a stacked structure of multiple tab layers 311, the inner tab layer 311 will appear longer after being bundled. Due to tolerance and other reasons, the top of the second tab 50 will have a misaligned area. 'b' refers to the length from the root 51 of the outermost tab layer 311 to the top of the most protruding tab layer 311 (usually the innermost tab layer 311) in the direction of the second tab 50's lead-out.

[0100] Furthermore, the ratio of L1 to b represents the degree to which the non-bonded region 73 covers the second electrode ear 50. A smaller ratio results in a smaller area of ​​the non-bonded region 73 covering the second electrode ear 50, which is beneficial for heat dissipation of the second electrode ear 50. However, a smaller ratio increases the risk of warping in the non-bonded region 73, potentially causing it to detach from the second electrode ear 50 and resulting in a short circuit. Conversely, a larger ratio results in a larger area of ​​the non-bonded region 73 covering the second electrode ear 50, which is detrimental to heat dissipation of the second electrode ear 50. However, a larger ratio decreases the risk of warping in the non-bonded region 73, potentially causing it to detach from the second electrode ear 50 and resulting in a short circuit.

[0101] For example, the ratio of L1 to b can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8, etc., or any value between the two values.

[0102] Optionally, in the lead-out direction of the second electrode ear 50, the size b of the second electrode ear 50 is in the range of 4 mm to 8 mm.

[0103] For example, the value of b can be 4mm, 5mm, 6mm, 7mm or 8mm, etc., or any value between two values.

[0104] like Figure 5 and Figure 6 As shown, in the technical solution of this embodiment, the diameter of the battery cell 30 is D, and the ratio of L1 to D is in the range of 0.05 to 0.3.

[0105] Specifically, the ratio of L1 to D represents the degree to which the non-adhesive region 73 covers the end face of the cell 30 in the radial direction, that is, the degree to which it covers the second electrode tab 50. The effect of an excessively large or small ratio of L1 to D on the second electrode tab 50 is similar to the meaning of the ratio of L1 to b mentioned above, so it will not be repeated here.

[0106] For example, the ratio of L1 to D can be chosen as 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, etc., or any value between the two values.

[0107] Optionally, the diameter of the cell 30 is in the range of 20mm to 70mm.

[0108] For example, the diameter of cell 30 can be selected as 20mm, 30mm, 40mm, 50mm, 60mm or 70mm, etc., or any value between two values.

[0109] like Figure 5 and Figure 6 As shown, in the technical solution of this embodiment, in the lead-out direction of the second electrode ear 50, the second electrode ear 50 has a bent portion 52, and the non-adhesive area 73 covers the bent portion 52.

[0110] Specifically, after the multiple tab layers 311 are gathered into a second tab portion 50, they are bent toward the end face of the cell 30, forming a bent portion 52. Since the bent portion 52 is the area most likely to overlap with the housing 10, the non-adhesive area 73 needs to cover the bent portion 52.

[0111] like Figure 5 and Figure 6 As shown, in the technical solution of this embodiment, the ratio of the overlapping area of ​​the non-adhesive area 73 and the second electrode ear 50 to the area of ​​the solder mark 60 is in the range of 0.1 to 0.75.

[0112] Specifically, the ratio of the overlapping area of ​​the non-adhesive region 73 to the second electrode ear 50 represents the degree to which the non-adhesive region 73 covers the second electrode ear 50. The effect of an excessively large or small ratio of the overlapping area of ​​the non-adhesive region 73 to the second electrode ear 50 on the second electrode ear 50 is similar to the meaning of the ratio of L1 to b mentioned above, and therefore will not be elaborated further.

[0113] For example, the ratio of the overlapping area of ​​the non-adhesive area 73 and the second electrode ear 50 to the area of ​​the solder mark 60 can be selected as 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, and 0.75, etc., as well as any value between the two values.

[0114] like Figure 6 and Figure 7 As shown, the insulation structure 70 does not cover the entire circumference of the cell 30, and at least one end of the non-adhesive area 73 extends beyond the side of the second electrode lug 50 in the width direction of the second electrode lug 50.

[0115] from Figure 3 As can be seen, there is a certain gap between the two ends of the insulation structure 70 along the circumference of the cell 30, that is, the insulation structure 70 does not cover the entire circumference of the cell 30.

[0116] Furthermore, in the width direction of the second pole ear 50, that is... Figure 5In the left-right direction. By making at least one end of the non-adhesive region 73 extend beyond the side of the second electrode ear 50, better insulation protection for the second electrode ear 50 can be achieved.

[0117] It should be noted that the non-adhesive area 73 can be a side that extends beyond the second pole ear 50 at one end, or the non-adhesive area 73 can be a side that extends beyond the second pole ear 50 at both ends.

[0118] like Figure 5 As shown, in the technical solution of this embodiment, the ratio of the width c of the second electrode tab 50 to the width d of the non-adhesive area 73 along the circumferential direction of the battery cell 30 is in the range of 0.1 to 0.8.

[0119] Specifically, the ratio of c to d represents the extent to which the non-adhesive area 73 extends beyond the second electrode tab 50 in the width direction. If this ratio is too large, the non-adhesive area 73 will extend too little beyond the second electrode tab 50, resulting in a still very close distance between the second electrode tab 50 and the casing 10, which may not meet the creepage distance requirements and could lead to arcing and short circuits during use. If this ratio is too small, the second electrode tab 50 will be relatively narrow, resulting in poor current carrying capacity and affecting the performance of the cylindrical battery.

[0120] Optionally, the ratio of the width c of the second electrode ear 50 to the width d of the non-adhesive area 73 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8, etc., or any value between the two values.

[0121] Optionally, the width c of the second pole ear 50 is in the range of 15mm to 60mm.

[0122] For example, the width c of the second pole ear 50 can be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm or 60mm, etc., or any value between two values.

[0123] Optionally, the width d of the non-adhesive area 73 is in the range of 21 mm to 160 mm.

[0124] For example, the width d of the non-adhesive area 73 can be 21mm, 25mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm or 160mm, etc., or any value between two values.

[0125] like Figure 5 and Figure 6As shown, the distance e of the non-adhesive area 73 extending beyond the side of the second pole ear 50 is in the range of 3mm to 60mm.

[0126] Specifically, if the value of e is too small, the non-adhesive area 73 will extend too little beyond the second tab 50. In this case, the distance between the second tab 50 and the casing 10 will still be very close, which may not meet the creepage distance requirements and may cause arcing and short circuits during use. If the value of e is too large, the second tab 50 will be relatively narrow, resulting in poor current carrying capacity and affecting the performance of the cylindrical battery.

[0127] For example, the value of e can be 3mm, 5mm, 10mm, 20mm, 30mm, 40mm, 50mm or 60mm, etc., as well as any value between two values.

[0128] like Figure 5 and Figure 6 As shown, in the technical solution of this embodiment, the ratio of the width d of the non-adhesive area 73 to the perimeter of the battery cell 30 is in the range of 0.15 to 1.

[0129] It should be noted that the width of the non-adhesive area 73 refers to the size of the non-adhesive area 73 along the circumference of the cell 30, or the size of the non-adhesive area 73 after being flattened. Figure 5 The dimensions in the left-right direction are shown. Since the insulation structure 70 in Embodiment 1 does not cover the entire circumference of the cell 30, this ratio cannot be 1.

[0130] It should be noted that the width d of the non-bonded area 73 and the circumference of the cell 30 are both in millimeters (mm).

[0131] Furthermore, if the ratio is small, the insulation protection capability of the second electrode ear 50 is weak; if the ratio is large, the non-bonded area 73 is more likely to warp when the top surface of the cell 30 is bent and folded, which may cause the second electrode ear 50 to overlap with the housing 10 and cause a short circuit.

[0132] For example, the ratio of the width d of the non-adhesive region 73 to the perimeter of the cell 30 can be selected as 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 0.99, etc., as well as any value between the two values.

[0133] Optionally, the circumference of the cell 30 is in the range of 314 mm to 3846.5 mm.

[0134] For example, the circumference of cell 30 can be 314mm, 350mm, 400mm, 500mm, 1000mm, 1500mm, 2000mm, 2500mm, 3000mm, 3500mm, 3800mm or 3846.5mm, etc., or any value between two values.

[0135] like Figure 5 and Figure 6 As shown, in the technical solution of this embodiment, the first electrode 40 and the second electrode 50 are led out from the same side of the battery cell 30, and further, 0.9≤(L1×L2) / L3≤245.

[0136] Specifically, since the first tab 40 and the second tab 50 are led out from the same side of the cell 30, the heat generation is relatively concentrated, and it is necessary to reduce the upper limit of (L1×L2) / L3 to improve the heat dissipation effect of the second tab 50.

[0137] For example, when the first electrode tab 40 and the second electrode tab 50 are led out from the same side of the cell 30, the value of (L1×L2) / L3 can be 0.9, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 or 245, etc., as well as any value between the two values.

[0138] In an embodiment not shown, the first tab 40 and the second tab 50 may also be led out from both sides of the battery cell 30. In this case, the heat generation at the second tab 50 is relatively reduced, and the heat dissipation requirement can be appropriately reduced. The upper limit of the preferred range of (L1×L2) / L3 can be 260, or any value between 245 and 260.

[0139] like Figure 2 , Figure 3 and Figure 6 As shown in the technical solution of this embodiment, the end of the battery cell 30 is provided with a first current collector 80 and a second current collector 90 spaced apart. The first current collector 80 is electrically connected to the first electrode tab 40, and the second current collector 90 is electrically connected to the second electrode tab 50.

[0140] Specifically, both the first current collector 80 and the second current collector 90 are roughly fan-shaped, and they are arranged opposite each other and roughly symmetrically along the center of the cell 30. Furthermore, the terminal 20 is connected to the side of the second current collector 90 facing the center of the cell 30.

[0141] like Figure 6As shown, in this embodiment, the non-adhesive region 73 is sandwiched between the second current collector 90 and the second electrode ear 50. On the axial projection of the cell 30, the overlap area between the non-adhesive region 73 and the second current collector 90 is 150 mm. 2 Up to 340mm 2 Within the range.

[0142] Specifically, the second current collector 90 is welded to the second electrode lug 50 and the electrode post 20, thus generating more heat. If the overlap area between the non-bonded area 73 and the second current collector 90 is too large, the insulation layer is prone to shrinkage due to severe heating. If the overlap area between the non-bonded area 73 and the second current collector 90 is too small, the coverage area of ​​the non-bonded area 73 on the second electrode lug 50 will be relatively small, weakening the insulation protection effect on the second electrode lug 50.

[0143] Optionally, the overlap area between the non-adhesive area 73 and the second current collector 90 can be 150 mm. 2 200mm 2 250mm 2 300mm 2 Or 340mm 2 And so on, as well as any value between two values.

[0144] like Figure 6 As shown, in the technical solution of this embodiment, the second current collector 90 is welded to the pole post 20, and the shortest distance f between the non-bonded area 73 and the pole post 20 is in the range of 10mm to 30mm.

[0145] Specifically, during assembly, the welding of the second current collector 90 to the terminal post 20 is later than the step of attaching the insulating structure 70. Therefore, when welding the second current collector 90 to the terminal post 20, the heat generated during welding may cause thermal shrinkage wrinkles in the non-bonded area 73.

[0146] Therefore, the shortest distance f between the non-adhesive region 73 and the pole post 20 needs to be controlled within a certain range. If the value of f is too large, the coverage area of ​​the non-adhesive region 73 on the second pole lug 50 will be relatively small, which will weaken the insulation protection effect on the second pole lug 50. If the value of f is too large, the insulation layer will be severely heated and prone to wrinkling when welding the pole post 20.

[0147] For example, the value of f can be 10mm, 15mm, 20mm, 25mm or 30mm, etc., or any value between two values.

[0148] like Figure 7 and Figure 8As shown, the battery cell 30 includes multiple electrode sheets 31 and a separator 32. The electrode sheet 31 includes a tab layer 311. The first tab portion 40 and the second tab portion 50 are both formed by the convergence of multiple tab layers 311. The junction between the tab layer 311 and the electrode sheet 31 is a rounded corner R. The radius of the rounded corner R is in the range of 1.5mm to 5mm.

[0149] Specifically, the base of the tab layer 311 and the base of the electrode sheet 31 is rounded with a radius R, which can reduce the risk of the base 51 of the second tab 50 being torn.

[0150] For example, the radius R can be 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, or any value between two values.

[0151] like Figure 7 and Figure 8 As shown, the battery cell 30 includes multiple electrode sheets 31 and a separator 32. The electrode sheet 31 includes a tab layer 311 extending from the first end of the electrode sheet 31. The first tab portion 40 and the second tab portion 50 are both formed by gathering multiple tab layers 311. The side of the tab layer 311 is inclined to the first end of the electrode sheet 31, and the angle of inclination r is in the range of 92° to 110°.

[0152] Specifically, for cylindrical batteries, the tab layer 311 gradually narrows towards the top, which is more in line with the tab closing method of the cylindrical cell 30 and prevents the top of the second tab 50 from exceeding the top of the cell 30.

[0153] For example, the tilt angle r can take values ​​of 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99°, 100°, 101°, 102°, 103°, 104°, 105°, 106°, 107°, 108°, 109°, or 110°, as well as any value between two values.

[0154] like Figure 4 As shown, in the technical solution of this embodiment, the ratio of the thickness g of the adhesive layer 72 of the insulating structure 70 to the thickness h of the insulating layer 71 is in the range of 1.25 to 4.

[0155] Specifically, if the ratio of the thickness g of the adhesive layer 72 of the insulating structure 70 to the thickness h of the insulating layer 71 is too small, it indicates that the thickness of the adhesive layer 72 is too small, which can easily weaken the bonding strength between the insulating structure 70 and the battery cell 30. If the ratio of the thickness g of the adhesive layer 72 of the insulating structure 70 to the thickness h of the insulating layer 71 is too large, it indicates that the thickness of the adhesive layer 72 is too large, which means that the distance between the non-bonded area 73 and the battery cell 30 is too far, and the non-bonded area 73 is more prone to warping, leading to a short circuit between the second electrode ear 50 and the housing 10.

[0156] Optionally, the ratio of the thickness g of the adhesive layer 72 of the insulating structure 70 to the thickness h of the insulating layer 71 can be selected as 1.25, 1.5, 2, 2.5, 3, 3.5 or 4, etc., or any value between the two values.

[0157] Optionally, the thickness g of the adhesive layer 72 is in the range of 0.02 mm to 0.2 mm.

[0158] For example, the thickness g of the adhesive layer 72 can be 0.02mm, 0.04mm, 0.06mm, 0.08mm, 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, or 0.2mm, etc., or any value between two values.

[0159] Optionally, the adhesive layer 72 can be made of one or more of the following: polyacrylic acid, polyolefin, polymethyl methacrylate, acrylic adhesive, silicone adhesive, etc.

[0160] Optionally, the thickness h of the insulating layer 71 is in the range of 0.01 mm to 0.05 mm.

[0161] For example, the thickness h of the insulating layer 71 can be selected as 0.01mm, 0.05mm, 0.02mm, 0.025mm, 0.03mm, 0.035mm, 0.04mm, 0.045mm or 0.05mm, etc., or any value between two values.

[0162] Optionally, the insulating layer 71 can be made of one or more of polyethylene terephthalate (PET), polypropylene (PP), polyimide (PI), polyolefin film, etc.

[0163] Example 2 like Figure 10 As shown, the difference between Embodiment 2 of the cylindrical battery according to this application and Embodiment 1 above is that the insulating structure 70 covers the cell 30 in the entire circumferential direction.

[0164] Although embodiments of the present 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 present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A cylindrical battery, characterized in that, include: Shell (10); A pole post (20) is disposed on the first end face (101) of the housing (10). A battery cell (30) is disposed inside the housing (10) and includes a second end face (301) and a peripheral face (302). A first electrode tab (40) and a second electrode tab (50) are led out from the second end face (301) of the battery cell (30). The first electrode tab (40) and the second electrode tab (50) have opposite polarities. The first electrode tab (40) is electrically connected to the housing (10) so that the housing (10) forms a first current output terminal. The second electrode tab (50) is electrically connected to the terminal post (20). A solder mark (60) is formed on the second electrode tab (50) so that the terminal post (20) forms a second current output terminal. An insulating structure (70) includes an insulating layer (71) and an adhesive layer (72) disposed on the insulating layer (71). The insulating structure (70) forms a non-adhesive region (73) in the area outside the adhesive layer (72). At least a portion of the adhesive layer (72) is adhered to the peripheral surface of the battery cell (30). The non-adhesive region (73) extends to the surface of the second electrode tab (50). In the radial direction of the battery cell (30), the dimension of the overlapping portion of the non-adhesive area (73) and the second electrode tab (50) is L1; in the axial direction of the battery cell (30), the bonding dimension of the adhesive layer (72) on the circumferential surface of the battery cell (30) is L2; ​​in the radial direction of the battery cell (30), the shortest distance from the end of the insulating structure (70) to the solder mark (60) is L3. 0.9mm ≤ (L1×L2) / L3 ≤ 260mm, The units for L1, L2, and L3 are mm.

2. The cylindrical battery according to claim 1, characterized in that, A connecting segment (303) is formed between the second end face (301) of the cell (30) and the peripheral surface (302), and the non-adhesive area (73) corresponds at least partially to the connecting segment (303).

3. The cylindrical battery according to claim 2, characterized in that, The non-adhesive area (73) extends from the connecting section (303) to the second end face (301) of the cell (30).

4. The cylindrical battery according to claim 1, characterized in that, The insulation structure (70) includes a first end point (701) and a second end point (702). The first end point (701) is fixed on the peripheral surface (302) of the battery cell (30), and the second end point (702) and the second end surface (301) of the battery cell (30) are disposed opposite to each other.

5. The cylindrical battery according to claim 4, characterized in that, The adhesive layer (72) extends from the first end point (701) and is spaced apart from the second end face (301) of the battery cell (30).

6. The cylindrical battery according to claim 1, characterized in that, The second electrode tab (50) is spaced apart from the edge of the second end face (301) of the battery cell (30), with the spacing distance (i) ranging from 0.2 mm to 1.2 mm.

7. The cylindrical battery according to claim 6, characterized in that, The second electrode portion (50) includes a plurality of single electrode tabs (53), the dimension (j) of which along its extension direction is greater than the edge spacing distance (i) between the second electrode portion (50) and the second end face (301) of the cell (30).

8. The cylindrical battery according to claim 1, characterized in that, The insulation structure (70) is continuously arranged in the direction of the circumferential surface (302) of the cell (30).

9. The cylindrical battery according to any one of claims 1 to 8, characterized in that, Along the radial direction of the cell (30), the size (k) of the insulating layer (71) is in the range of 3 mm to 25 mm.

10. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The L2 is in the range of 5mm to 25mm.

11. The cylindrical battery according to claim 10, characterized in that, Along the axial direction of the battery cell (30), the height of the battery cell (30) is H, and the ratio of L2 to H is in the range of 0.03 to 0.5; and / or, The height (H) of the battery cell (30) is in the range of 50 mm to 200 mm.

12. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The L1 ranges from 0.5 mm to 6 mm.

13. The cylindrical battery according to claim 12, characterized in that, In the lead-out direction of the second electrode ear (50), the size of the second electrode ear (50) is b, and the ratio of L1 to b is in the range of 0.1 to 0.8; and / or, In the lead-out direction of the second electrode ear (50), the size (b) of the second electrode ear (50) is in the range of 4 mm to 8 mm.

14. The cylindrical battery according to claim 12, characterized in that, The diameter of the battery cell (30) is D, and the ratio of L1 to D is in the range of 0.05 to 0.3; and / or, The diameter of the battery cell (30) is in the range of 20 mm to 70 mm.

15. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The L3 is in the range of 0.5 mm to 4 mm.

16. The cylindrical battery according to any one of claims 1 to 8, characterized in that, In the lead-out direction of the second electrode ear (50), the second electrode ear (50) has a bent portion (52), and the non-adhesive area (73) covers the bent portion (52).

17. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The ratio of the overlapping area of ​​the non-adhesive area (73) and the second electrode ear (50) to the area of ​​the solder mark (60) is in the range of 0.1 to 0.

75.

18. The cylindrical battery according to any one of claims 1 to 8, characterized in that, Along the circumferential direction of the cell (30), at least one end of the non-adhesive region (73) extends beyond the side of the second electrode tab (50).

19. The cylindrical battery according to claim 18, characterized in that, Along the circumferential direction of the battery cell (30), the ratio of the width (c) of the second electrode tab (50) to the width (d) of the non-adhesive region (73) is in the range of 0.1 to 0.8; and / or, The width (c) of the second pole ear (50) is in the range of 15 mm to 60 mm; and / or, The width (d) of the non-adhesive area (73) is in the range of 21 mm to 160 mm.

20. The cylindrical battery according to claim 18, characterized in that, The distance (e) by which the non-adhesive area (73) extends beyond the side of the second pole ear (50) is in the range of 3 mm to 60 mm.

21. The cylindrical battery according to claim 18, characterized in that, The width (d) of the non-adhesive area (73) ranges from 21 mm to 160 mm.

22. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The first tab (40) and the second tab (50) are led out from the same side of the cell (30), and 0.9≤(L1×L2) / L3≤245.

23. The cylindrical battery according to claim 22, characterized in that, The end of the battery cell (30) is provided with a first current collector (80) and a second current collector (90) spaced apart. The first current collector (80) is electrically connected to the first electrode tab (40), and the second current collector (90) is electrically connected to the second electrode tab (50).

24. The cylindrical battery according to claim 23, characterized in that, The non-adhesive region (73) is sandwiched between the second current collector (90) and the second electrode tab (50). On the axial projection of the cell (30), the overlap area between the non-adhesive region (73) and the second current collector (90) is approximately 150 mm. 2 Up to 340mm 2 Within the range.

25. The cylindrical battery according to claim 23, characterized in that, The second current collector (90) is welded to the pole (20), and the shortest distance (f) between the non-bonded area (73) and the pole (20) is in the range of 10 mm to 30 mm.

26. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The battery cell (30) includes multiple electrode sheets (31) and a separator (32). The electrode sheet (31) includes a tab layer (311). The first tab portion (40) and the second tab portion (50) are both formed by the convergence of multiple tab layers (311). The junction between the tab layer (311) and the electrode sheet (31) is a rounded corner (R). The radius of the rounded corner (R) is in the range of 1.5 mm to 5 mm.

27. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The battery cell (30) includes multiple electrode sheets (31) and a separator (32). The electrode sheet (31) includes a tab layer (311) extending from the first end of the electrode sheet (31). The first tab portion (40) and the second tab portion (50) are both formed by the convergence of multiple tab layers (311). The side of the tab layer (311) is inclined to the first end of the electrode sheet (31), and the angle of inclination (r) is in the range of 92° to 110°.

28. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The ratio of the thickness (g) of the adhesive layer (72) of the insulating structure (70) to the thickness (h) of the insulating layer (71) is in the range of 1.25 to 4; and / or, The thickness (g) of the adhesive layer (72) is in the range of 0.02 mm to 0.2 mm; and / or, The thickness (h) of the insulating layer (71) is in the range of 0.01 mm to 0.05 mm.

29. The cylindrical battery according to any one of claims 1 to 8, characterized in that, The adhesive layer (72) does not overlap with the root (51) of the second electrode ear (50), and the distance a between the end of the adhesive layer (72) and the root (51) of the second electrode ear (50) is in the range of 0.5 mm to 4 mm.

Images