Battery

Abstract

The invention provides a battery which comprises a battery cell, a shell, a positive pole assembly and a negative pole assembly, the battery cell comprises a battery cell body, a positive tab and a negative tab, in the length direction of the battery, the positive tab and the negative tab are led out from the two ends of the battery cell body, and the positive tab and the negative tab are welded to the positive pole assembly and the negative pole assembly respectively; the thickness of the positive pole lug is larger than that of the negative pole lug, the width W1 of the negative pole lug in the width direction of the battery is larger than the width W2 of the positive pole lug in the width direction of the battery, and the widths of the welding area of the negative pole lug and the negative pole column assembly and the welding area of the positive pole lug and the positive pole column assembly in the width direction of the battery are W3 and W4 respectively; and 0.1 < = (W1-W3) / (W2-W4) < = 20. The battery is relatively high in energy density, relatively high in reliability and relatively good in overall overcurrent capability, and the connection strength of the positive and negative pole lug and pole column assemblies is enough and relatively balanced.

Description

[0001] This application is a divisional application based on the original invention patent application number 2024114283194, the application date is October 14, 2024, and the application name is "A Battery". Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery. Background Art

[0003] The battery includes a positive electrode tab, a negative electrode tab, a positive electrode column assembly and a negative electrode column assembly. The positive and negative tabs are welded to the positive and negative electrode column assemblies respectively to form a charge and discharge circuit. If the connection between the positive and negative tabs and the positive and negative electrode column assemblies is broken, the electrical connection of the battery will fail, which is not conducive to the reliable operation of the battery. If the positive and negative electrode overcurrent capacity is unbalanced, the overall overcurrent capacity of the battery will be poor. Summary of the invention

[0004] The purpose of this application is to provide a battery with higher energy density and higher reliability.

[0005] The battery provided in the present application comprises a battery cell, a shell, a positive electrode column assembly and a negative electrode column assembly, wherein the battery cell is located in the shell, the positive electrode column assembly and the negative electrode column assembly are arranged in the shell, the battery cell comprises a battery cell body, a positive electrode tab and a negative electrode tab, in the length direction of the battery, the positive electrode tab and the negative electrode tab are respectively led out from both ends of the battery cell body, the positive electrode tab and the negative electrode tab are respectively welded to the positive electrode column assembly and the negative electrode column assembly, the length of the battery is L, L≥400mm, the thickness of the positive electrode tab is greater than the thickness of the negative electrode tab, the width of the negative electrode tab in the width direction of the battery is W1, the width of the positive electrode tab in the width direction of the battery is W2, W1>W2;

[0006] The width of the welding area between the negative electrode tab and the negative electrode column assembly in the width direction of the battery is W3, and the width of the welding area between the positive electrode tab and the positive electrode column assembly in the width direction of the battery is W4, 0.1≤(W1-W3) / (W2-W4)≤20.

[0007] Since the length of the battery is greater than or equal to 400mm, the length of the battery body is also relatively long. The longer the length of the battery body is, the more conducive it is to improving the energy density of the battery. In addition, since the negative pole ear of the battery is relatively thin (the thickness of the negative pole ear is less than the thickness of the positive pole ear), the negative pole ear monolith (multiple negative pole ear monoliths are stacked to form the negative pole ear) is also relatively thin (the thickness of the negative pole ear monolith is less than the thickness of the positive pole ear monolith), so the current collector of the negative pole sheet of the battery body (the negative pole ear monolith is drawn from the current collector of the negative pole sheet of the battery body) is also relatively thin. When the thickness of the negative pole sheet is constant, the thinner the current collector of the negative pole sheet, the thicker the active material layer coated on both sides of the current collector of the negative pole sheet, the thicker the active material layer, the more conducive it is to improving the energy density of the battery, so the energy density of the battery is relatively high.

[0008] Since the negative electrode tab is relatively thin (the thickness of the negative electrode tab is smaller than that of the positive electrode tab), the connection position between the negative electrode tab and the negative electrode post assembly is prone to breakage, resulting in poor battery reliability. In addition, the battery is relatively long. The longer the battery is, the greater the force on the connection position between the negative electrode tab and the negative electrode post assembly at one end of the battery length is, which further increases the risk of breakage at the connection position between the negative electrode tab and the negative electrode post assembly. The present application improves the strength of the connection position between the negative electrode tab and the negative electrode post assembly by making the width of the negative electrode tab greater than the width of the positive electrode tab, reduces the risk of breakage at the connection position between the negative electrode tab and the negative electrode post assembly, and thus makes the battery have higher reliability.

[0009] If (W1-W3) / (W2-W4) is too large, it means that W1-W3 is too large and / or W2-W4 is too small. If W1-W3 is too large, the connection strength between the negative electrode tab 23 and the negative electrode column assembly 32 will be insufficient. If (W1-W3) / (W2-W4) is too small, it means that W2-W4 is too large and / or W1-W3 is too small. If W2-W4 is too large, the connection strength between the positive electrode tab 22 and the positive electrode column assembly 31 will be insufficient. 0.1≤(W1-W3) / (W2-W4)≤20 can ensure that the connection strength between the negative electrode tab 23 and the negative electrode column assembly 32 and the connection strength between the positive electrode tab 22 and the positive electrode column assembly 31 are sufficient and relatively balanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 An exploded view of an embodiment of a battery provided in the present application;

[0011] Figure 2 for Figure 1 Another perspective of the assembled state;

[0012] Figure 3 for Figure 1 A schematic plan view of the battery cell and cover plate;

[0013] Figure 4 for Figure 1 An enlarged view of the location of the negative electrode tab after the negative electrode insulation protective cover is hidden;

[0014] Figure 5 for Figure 1 A magnified view of the positive electrode insulation shield;

[0015] Figure 6 A simplified diagram of the cell structure of an embodiment of the battery provided in the present application;

[0016] Figure 7 A simplified diagram of the shell structure of an embodiment of a battery provided in the present application.

[0017] The following are the descriptions of the reference numerals:

[0018] 1 shell body, 11 shell body, 11a raised portion, 11b recessed portion, 12 cover plate, C liquid injection hole;

[0019] 2 battery cell, 21 battery cell body, 22 positive electrode tab, 23 negative electrode tab;

[0020] 31 positive pole assembly, 32 negative pole assembly;

[0021] 4 adapters;

[0022] 51 positive electrode insulation protection cover, 52 negative electrode insulation protection cover, 5a first support part, A first side wall, 5b second support part, B second side wall, 5c pole ear accommodating part. DETAILED DESCRIPTION

[0023] The present application provides a battery. In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0024] like Figure 1-Figure 4 As shown, the battery comprises a housing 1, a battery cell 2 and a pole assembly. The housing 1 is provided with a liquid injection hole C (see Figure 2 ), and electrolyte is injected into the housing 1 through the injection hole C. The battery cell 2 is located in the housing 1. The pole assembly is arranged in the housing 1. The pole assembly includes a positive pole assembly 31 and a negative pole assembly 32. The positive pole assembly 31 includes at least a positive pole, and an adapter 4 may be optionally provided. The negative pole assembly 32 includes at least a negative pole, and an adapter 4 may be optionally provided.

[0025] The battery cell 2 includes a battery cell body 21 and tabs. The tabs include a positive tab 22 and a negative tab 23. In the length direction of the battery, the positive tab 22 and the negative tab 23 are respectively led out from the two ends of the battery cell body 21. The battery as a whole is roughly rectangular, including two large-area surfaces arranged opposite to each other and four small-area surfaces located between the two large-area surfaces. The long side direction of the large-area surface is the length direction of the battery, the short side direction of the large-area surface is the width direction of the battery, and the direction perpendicular to the large-area surface is the thickness direction of the battery. The length direction, width direction and thickness direction of the battery are perpendicular to each other.

[0026] The positive electrode tab 22 is welded to the positive electrode post assembly 31, and the negative electrode tab 23 is welded to the negative electrode post assembly 32. If the positive electrode post assembly 31 is not provided with an adapter 4, the positive electrode tab 22 is welded to the positive electrode post. If the positive electrode post assembly 31 is provided with an adapter 4, the positive electrode tab 22 is welded to one side of the adapter 4, and the positive electrode post is welded to the other side of the adapter 4. If the negative electrode post assembly 32 is not provided with an adapter 4, the negative electrode tab 23 is welded to the negative electrode post. If the negative electrode post assembly 32 is provided with an adapter 4, the negative electrode tab 23 is welded to one side of the adapter 4, and the negative electrode post is welded to the other side of the adapter 4.

[0027] The battery cell body 21 includes a positive electrode sheet and a negative electrode sheet, which are arranged alternately one by one, and a separator is provided between adjacent positive electrode sheets and negative electrode sheets. In some embodiments, the positive electrode sheets and the negative electrode sheets are arranged alternately one by one along the thickness direction of the battery, so that the battery cell body 21 is a laminated structure. In some embodiments, the positive electrode sheets and the negative electrode sheets are wound, and the positive electrode sheets and the negative electrode sheets are arranged alternately one by one along a direction perpendicular to the winding center line, so that the battery cell body 21 is a rolled structure.

[0028] The structures of the positive electrode sheet and the negative electrode sheet are similar, both of which include a current collector and an active material layer coated on both sides of the current collector. The active material layer of the positive electrode sheet includes a positive electrode active material, a conductive agent, a binder, etc. The positive electrode active material includes a nickel-cobalt-manganese ternary material, a lithium iron phosphate material, a lithium iron manganese phosphate material, a lithium nickel manganese oxide material, etc. The active material layer of the negative electrode sheet includes a negative electrode active material, a conductive agent, a binder, etc. The negative electrode active material includes artificial graphite, natural graphite, silicon-based materials, etc. This application does not limit the material of the current collector, as long as it has conductivity and does not cause adverse chemical changes in the battery. For example, stainless steel, aluminum, nickel, titanium, fired carbon, or aluminum or stainless steel with a surface treatment of one of carbon, nickel, titanium, silver, etc. can be used.

[0029] The part of the current collector of the positive electrode sheet that is not coated with the active material protrudes from the part that is coated with the active material to form a positive electrode tab single piece. Multiple layers of positive electrode tab single pieces are stacked to form a positive electrode tab 22. The part of the current collector of the negative electrode sheet that is not coated with the active material protrudes from the part that is coated with the active material to form a negative electrode tab single piece. Multiple layers of negative electrode tab single pieces are stacked to form a negative electrode tab 23.

[0030] The length of the battery is L, L ≥ 400 mm, for example, L can be equal to 500 mm, 600 mm, 700 mm. The longer the length of the battery is, the longer the length of the battery body 21 is, and the more conducive it is to improve the battery energy density.

[0031] The thickness of the positive electrode tab 22 is greater than the thickness of the negative electrode tab 23, the thickness of the positive electrode tab monolith is greater than the thickness of the negative electrode tab monolith, the thickness of the positive electrode tab 22 is equal to the number of positive electrode tab monoliths multiplied by the thickness of the positive electrode tab monolith, and the thickness of the negative electrode tab 23 is equal to the number of negative electrode tab monoliths multiplied by the thickness of the negative electrode tab monolith. Since the negative electrode tab monolith is drawn from the current collector of the negative electrode tab, the thinner the thickness of the negative electrode tab monolith, the thinner the thickness of the current collector of the negative electrode tab. When the thickness of the negative electrode tab is constant, the thinner the current collector of the negative electrode tab, the thicker the active material layer of the negative electrode tab, the thicker the active material layer, the more conducive to improving the battery energy density.

[0032] The width of the negative electrode tab 23 in the battery width direction is W1, and the width of the positive electrode tab 22 in the battery width direction is W2, where W1>W2.

[0033] Since the negative electrode tab 23 is relatively thin (the thickness of the negative electrode tab 23 is less than the thickness of the positive electrode tab 22), the connection position between the negative electrode tab 23 and the negative electrode column assembly 32 is prone to breakage, resulting in poor reliability of the battery. In addition, the length of the battery is relatively long (greater than or equal to 400 mm). The longer the length of the battery, the greater the force on the connection position between the negative electrode tab 23 and the negative electrode column assembly 32 at one end of the battery length, which further increases the risk of breakage at the connection position between the negative electrode tab 23 and the negative electrode column assembly 32. The present application improves the strength of the connection position between the negative electrode tab 23 and the negative electrode column assembly 32 by making the width of the negative electrode tab 23 greater than the width of the positive electrode tab 22, reduces the risk of breakage at the connection position between the negative electrode tab 23 and the negative electrode column assembly 32, and thus makes the battery have higher reliability.

[0034] In addition, since the thickness of the negative electrode tab 23 is relatively thin (the thickness of the negative electrode tab 23 is less than the thickness of the positive electrode tab 22), the negative electrode current capacity is not as good as the positive electrode current capacity, resulting in poor overall battery current capacity. In addition, the length of the battery is relatively long (greater than or equal to 400 mm). The longer the length of the battery, the greater the impedance, which further aggravates the difference between the negative electrode current capacity and the positive electrode current capacity. In this application, by making the width of the negative electrode tab 23 greater than the width of the positive electrode tab 22, the width of the welding area between the negative electrode tab 23 and the negative electrode column assembly 32 can be designed to be greater than the width of the welding area between the positive electrode tab 22 and the positive electrode column assembly 31, thereby improving the negative electrode current capacity and making the positive and negative electrode current capacities more balanced, thereby making the overall battery current capacity better.

[0035] By comprehensively controlling the relationship between the length L of the battery and W1-W2, the consistency of the connection strength between the positive electrode tab 22 and the positive electrode column assembly 31 and the negative electrode tab 23 and the negative electrode column assembly 32 can be improved to avoid the connection failure of the thinner negative electrode tab 23 and the negative electrode column assembly 32. Specifically, the range of L / (W1-W2) is controlled to: 9≤L / (W1-W2)≤600. For example, L / (W1-W2) can be equal to 9, 10, 30, 60, 100, 200. , 300, 500. If the ratio is too large, it means that L is too large and / or W1-W2 is too small. If W1-W2 is too small, it means that W2 is too large or W1 is too small. If W1 is too small, the connection strength between the negative electrode tab 23 and the negative electrode column assembly 32 will be insufficient, which may cause the connection to break easily and result in low reliability of the battery. If W2 is too large, the positive electrode tab 22 will transition and hinder the electrolyte in the shell 1 from flowing from the end where the positive electrode tab 22 is drawn out to the battery cell body 21, which is not conducive to the rapid and uniform infiltration of the electrolyte into the battery cell body 21. If the ratio is too small, it means that L is too small and / or W1-W2 is too large. If W1-W2 is too large, it means that W2 is too small or W1 is too large. If W1 is too large, the negative pole tab 23 will cause the electrolyte in the shell 1 to flow from the end where the negative pole tab 23 is drawn out to the battery body 21, which is not conducive to the electrolyte quickly and evenly infiltrating the battery body 21. If W2 is too small, the connection strength between the positive pole tab 22 and the positive pole column assembly 31 is insufficient, which is easy to break and cause the battery reliability to be low. 9≤L / (W1-W2)≤600, which can ensure that the electrolyte can quickly and evenly infiltrate the battery body 21 and the battery has high reliability. Moreover, this range makes the battery length L positively correlated with the width W1 of the negative pole tab 23 when the width W2 of the positive pole tab 22 is constant, that is, the larger L is, the larger W1 is, and the smaller L is, the smaller W1 is. The larger L is, the greater the force on the connection between the negative electrode tab 23 and the negative electrode post assembly 32 is, and the greater the risk of breakage at the connection between the negative electrode tab 23 and the negative electrode post assembly 32 is. Therefore, it is necessary to make the width W1 of the negative electrode tab 23 larger to increase the strength of the connection between the negative electrode tab 23 and the negative electrode post assembly 32 to a greater extent.

[0036] In some embodiments, 0.05≤(W-W1) / (W-W2)≤0.98, for example, (W-W1) / (W-W2) may be equal to 0.1, 0.4, 0.6, 0.8, or 0.9. Wherein, W is the width of the cell body in the length direction of the battery. If the ratio is too large, it means that W-W1 is too large and / or W-W2 is too small, resulting in an unbalanced connection strength between the positive and negative tabs and the positive and negative column assemblies; if the ratio is too small, it means that W-W1 is too small and / or W-W2 is too large, resulting in an unbalanced connection strength between the positive and negative tabs and the positive and negative column assemblies.

[0037] In some embodiments, 10mm≤W-W1≤100mm, for example, W-W1 can be equal to 10mm, 15mm, 20mm, 50mm, 70mm, 90mm, 100mm. If the difference is too large, it means that W1 is too small, resulting in poor connection strength between the negative electrode tab 23 and the negative electrode column assembly 32, causing the connection strength between the positive and negative tabs and the positive and negative electrode column assemblies to be unbalanced, and failing to improve the negative electrode current capacity well, thereby failing to make up for the lack of negative electrode current capacity caused by the thickness of the negative electrode tab 23 being less than the thickness of the positive electrode tab 22; if the difference is too small, it means that W1 is too large, causing the negative electrode tab 23 to transitionally hinder the electrolyte in the shell 1 from the end where the negative electrode tab 23 is drawn out to the battery body 21, which is not conducive to the electrolyte quickly and evenly infiltrating the battery body 21. Specifically, the width W1 of the negative electrode tab 23 in the width direction of the battery may be in the range of 15 mm ≤ W1 ≤ 80 mm. For example, W1 may be equal to 15 mm, 30 mm, 50 mm, 60 mm, or 80 mm.

[0038] In some embodiments, 12mm≤W-W2≤100mm, for example, W-W2 can be equal to 13mm, 20mm, 50mm, 70mm, 90mm. If the difference is too large, it means that W2 is too small, resulting in poor connection strength between the positive electrode tab 22 and the positive electrode column assembly 31, causing uneven connection strength between the positive and negative tabs and the positive and negative electrode column assemblies; if the difference is too small, it means that W2 is too large, causing the positive electrode tab 22 to transitionally hinder the electrolyte in the shell 1 from the end where the positive electrode tab 22 is drawn out to the battery body 21, which is not conducive to the electrolyte quickly and evenly infiltrating the battery body 21. Specifically, the width W2 of the positive electrode tab 22 in the battery width direction can be in the range of: 13mm≤W2≤60mm, for example, W2 can be equal to 20mm, 40mm, 50mm.

[0039] In some embodiments, 1.1≤W3 / W4≤8, for example, W3 / W4 can be equal to 1.1, 2, 3, 5, 6, 6.5, 8. Wherein, W3 is the width of the welding area between the negative electrode tab 23 and the negative electrode column assembly 32 in the battery width direction, and W4 is the width of the welding area between the positive electrode tab 22 and the positive electrode column assembly 31 in the battery width direction. Since the lower limit of the ratio is greater than 1, W3 is greater than W4, and W3 is greater than W4, which can make up for the lack of negative electrode current capacity caused by the thickness of the negative electrode tab 23 being less than the thickness of the positive electrode tab 22. If the ratio is too large, it means that W3 is too large, and W3 is too large, which will cause the positive electrode current capacity to be less than the negative electrode current capacity, resulting in poor overall battery current capacity. If the ratio is too small, it means that W3 is too small, and W3 is too small to make up for the lack of negative electrode current capacity caused by the thickness of the negative electrode tab 23 being less than the thickness of the positive electrode tab 22.

[0040] In some embodiments, 0.1≤(W1-W3) / (W2-W4)≤20, for example, (W1-W3) / (W2-W4) can be equal to 0.1, 1, 5, 10, 15. If the ratio is too large, it means that W1-W3 is too large and / or W2-W4 is too small. If W1-W3 is too large, the connection strength between the negative electrode tab 23 and the negative electrode column assembly 32 will be insufficient. If the ratio is too small, it means that W2-W4 is too large and / or W1-W3 is too small. If W2-W4 is too large, the connection strength between the positive electrode tab 22 and the positive electrode column assembly 31 will be insufficient. 0.1≤(W1-W3) / (W2-W4)≤20, this range can ensure that the connection strength between the negative electrode tab 23 and the negative electrode column assembly 32 and the connection strength between the positive electrode tab 22 and the positive electrode column assembly 31 are sufficient and relatively balanced.

[0041] In some embodiments, 5mm≤W1-W3≤70mm, W1-W3 is the width of the portion of the negative electrode tab 23 that is not welded to the negative electrode post assembly 32. The larger W1-W3 is, the higher the connection strength between the negative electrode tab 23 and the negative electrode sheet is, but it means that the smaller W3 is, the lower the connection strength between the negative electrode tab 23 and the negative electrode post assembly 32 is. 5mm≤W1-W3≤70mm, this range makes the connection strength between the negative electrode tab 23 and the negative electrode post assembly 32 and the negative electrode sheet relatively high and balanced. Specifically, the width W3 of the welding area between the negative electrode tab 23 and the negative electrode post assembly 32 in the battery width direction can be in the range of: 10mm≤W3≤55mm, for example, W3 can be equal to 20mm, 40mm, 50mm.

[0042] In some embodiments, 8mm≤W2-W4≤75mm, where W2-W4 is the width of the portion of the positive electrode tab 22 that is not welded to the positive electrode column assembly 31. The larger W2-W4 is, the higher the connection strength between the positive electrode tab 22 and the positive electrode sheet is, but it means that the smaller W4 is, the lower the connection strength between the positive electrode tab 22 and the positive electrode column assembly 31 is. 8mm≤W2-W4≤75mm, this range makes the connection strength between the positive electrode tab 22 and the positive electrode column assembly 31 and the positive electrode sheet relatively high and balanced. Specifically, the width W4 of the welding area between the positive electrode tab 22 and the positive electrode column assembly 31 in the battery width direction can be in the range of: 5mm≤W4≤50mm, for example, W4 can be equal to 5mm, 10mm, 30mm, 40mm, 50mm.

[0043] In some embodiments, the positive projection of the negative electrode tab 23 on the plane where the injection hole is located overlaps with the injection hole at least partially. With this design, when the battery width is constant, the width W1 of the negative electrode tab 23 can be set wider, and accordingly, the width W3 of the welding area between the negative electrode tab 23 and the negative electrode column assembly 32 can also be set wider, so as to be sufficient to make up for the lack of negative electrode current capacity caused by the thickness of the negative electrode tab 23 being less than the thickness of the positive electrode tab 22, and to ensure that the negative electrode tab 23 and the negative electrode column assembly 32 have sufficient connection strength. In addition, when overlapping, the negative electrode tab 23 can prevent the electrolyte coming in from the injection hole from directly impacting the battery body, thereby protecting the battery body. In this case, the range of W-W1 can be further narrowed to: 10mm≤W-W1≤85mm.

[0044] In some embodiments, the orthographic projection of the positive electrode tab 22 on the plane where the injection hole is located overlaps at least partially with the injection hole. With this design, when the battery width is constant, the width W2 of the positive electrode tab 22 can be set wider, so as to ensure that the positive electrode tab 22 and the positive electrode column assembly 31 have sufficient connection strength. In addition, when overlapping, the positive electrode tab 22 can block the electrolyte coming in from the injection hole from directly impacting the battery cell body, thereby protecting the battery cell body. In this case, the range of W-W2 can be further narrowed to: 15mm≤W-W2≤100mm.

[0045] In some embodiments, the positive projection of the negative electrode tab 23 on the plane where the injection hole is located does not overlap with the injection hole. With this design, when the battery width is constant, the width W1 of the negative electrode tab 23 is narrower, thereby avoiding uneven electrolyte infiltration caused by the negative electrode tab 23 being too wide.

[0046] In some embodiments, the positive electrode tab 22 has an orthographic projection on the plane where the injection hole is located, which does not overlap with the injection hole. With this design, when the battery width is constant, the width W2 of the positive electrode tab 22 is narrower, thereby avoiding uneven electrolyte infiltration caused by the positive electrode tab 22 being too wide.

[0047] In some embodiments, the injection hole is arranged at one end of the positive electrode ear 22, and the positive projection of the positive electrode ear 22 on the plane where the injection hole is located does not overlap with the injection hole. Since the thickness of the positive electrode ear 22 is relatively thick, the obstruction to the electrolyte is more serious. Therefore, the positive electrode ear 22 is not overlapped with the injection hole, which can reduce the obstruction of the positive electrode ear 22 to the electrolyte, thereby compensating for the uneven electrolyte infiltration caused by the thickness of the positive electrode ear 22. In this case, in the length direction of the battery, the distance between the injection hole and the battery body is L1, 2mm≤L1≤10mm. Since the positive electrode ear 22 and the injection hole do not overlap, the electrolyte will directly impact the battery body during injection. 2mm≤L1 can ensure that the impact force of the electrolyte on the electrode sheet will not be too large, and L1 cannot be too large. Too large will cause excessive flow resistance in the process of the electrolyte flowing to the battery body, which is not conducive to the uniform infiltration of the electrolyte into the battery body.

[0048] In some embodiments, Figure 6 As shown, a transition portion is provided between the negative pole tab 23 and the battery cell body 21. The transition portion acts as a buffer to reduce the possibility of fracture between the negative pole tab 23 and the battery cell body 21. Therefore, the width W3 of the welding area of ​​the negative pole tab 23 can be set larger to increase the connection strength between the negative pole tab 23 and the negative pole column assembly 32. The radius of the transition portion between the negative pole tab 23 and the battery cell body is R1. The larger R1 is, the more conducive it is to reduce the possibility of fracture between the negative pole tab 23 and the battery cell body. Therefore, the larger R1 is, the larger W3 can be set, and the smaller W1-W3 is. Therefore, R1*(W1-W3) should be within a certain range. Specifically, the range can be 6mm. 2 ≤R1*(W1-W3)≤350mm 2 , for example R1*(W1-W3) can be equal to 10 mm 2 , 50 mm 2 , 100 mm 2 , 200 mm 2 , 300 mm 2 .

[0049] In some embodiments, Figure 6As shown, a transition portion is provided between the positive pole tab 22 and the battery cell body 21. The transition portion acts as a buffer to reduce the possibility of fracture between the positive pole tab 22 and the battery cell body 21. Therefore, the width W4 of the welding area of ​​the positive pole tab 22 can be set larger to increase the connection strength between the positive pole tab 22 and the positive pole column assembly 31. The radius of the transition portion between the positive pole tab 22 and the battery cell body 21 is R2. The larger R2 is, the more conducive it is to reduce the possibility of fracture between the positive pole tab 22 and the battery cell body. Therefore, the larger R2 is, the larger W4 can be set, and the smaller W2-W4 is. Therefore, R2*(W2-W4) should be within a certain range. Specifically, the range can be: 10 mm 2 ≤R2*(W2-W4)≤360mm 2 , for example R2*(W2-W4) can be equal to 10 mm 2 , 50 mm 2 , 100 mm 2 , 200 mm 2 , 300 mm 2 , 350 mm 2 , 360 mm 2 .

[0050] In some embodiments, Figure 7 As shown, the shell 1 includes a shell body 11 and two cover plates 12. In the length direction of the battery, the two ends of the shell body 11 are open, and the two cover plates 12 respectively close the two end openings. The positive electrode column assembly 31 is arranged on one cover plate 12, and the negative electrode column assembly 32 is respectively arranged on the other cover plate 12. The injection hole C is arranged on one of the cover plates 12.

[0051] In some embodiments, Figure 1As shown, the shell 1 includes a shell body 11 and a cover plate 12. In the thickness direction of the battery, one side of the shell body 11 is open, and the cover plate 12 closes the opening. In the length direction of the battery, the positive pole column assembly 31 and the negative pole column assembly 32 are respectively arranged at the two ends of the cover plate 12. In the length direction of the battery, the shell body 11 is provided with a recessed portion 11b at both ends, and a raised portion 11a is provided in the middle. The positive pole ear 22 and the negative pole ear 23 are respectively located in the two recessed portions 11b in the raised portion 11a of the battery cell body 21. The recessed portion 11b can be used to accommodate the pole assemblies of adjacent batteries when the batteries are grouped, thereby improving the space utilization rate of the box. When the recessed portion 11b is formed, a transition angle is formed at both ends in its width direction (which is also the width direction of the battery). The negative electrode tab 23 needs to avoid the transition angle of the recess where it is located. Therefore, in the width direction of the battery, D between the negative electrode tab 23 and the side wall of the recess where it is located should have a lower limit value. If D is too large, the width of the negative electrode tab 23 will be too small. Therefore, D should also have an upper limit value. Specifically, the range of D can be: 2mm≤D≤20mm. For example, D can be equal to 3mm, 5mm, 10mm, or 15mm.

[0052] In some embodiments, Figure 1 As shown, the battery includes an insulating protective cover, which includes a positive insulating protective cover 51 and a negative insulating protective cover 52. The positive insulating protective cover 51 is located in the housing 1, specifically in the recessed portion 11b where the positive pole tab 22 is located, and serves as an insulation between the positive pole column assembly 31 and the battery cell body 21. The negative insulating protective cover 52 is located in the housing 1, specifically in the recessed portion 11b where the negative pole tab 23 is located, and serves as an insulation between the negative pole column assembly 32 and the battery cell body 21.

[0053] The structures of the positive electrode insulation protection cover 51 and the negative electrode insulation protection cover 52 are similar. Figure 5 As shown, a first support portion 5a, a tab accommodating portion 5c, and a second support portion 5b are sequentially provided along the width direction of the battery, a first side wall A is provided on the side of the first support portion 5a close to the tab accommodating portion 5c, and a second side wall B is provided on the side of the second support portion 5b close to the tab accommodating portion 5c. The insulating protective cover is also provided with a flip cover (not shown in the figure), after the tab is connected to the pole column assembly, the flip cover is closed, and the flip cover is clamped together with the first side wall A and the second side wall B after closing.

[0054] In some embodiments, at least one of the first side wall A and the second side wall B of the negative electrode insulation protective cover 52 is recessed in a direction away from the pole ear accommodating portion 5c to form a concave cavity and / or a hole is partially provided, and a portion of the negative electrode pole ear 23 is located in the concave cavity and / or the hole. In this way, sufficient accommodation space can be provided for the negative electrode pole ear 23 with a larger width. The concave cavity formed on the first side wall A and the second side wall B can improve the strength of the first side wall A and the second side wall B.

[0055] The above specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the present application.

Claims

1. A battery, characterized in that: The battery comprises a battery cell, a shell, a positive electrode column assembly and a negative electrode column assembly, the battery cell is located in the shell, the positive electrode column assembly and the negative electrode column assembly are arranged in the shell, the battery cell comprises a battery cell body, a positive electrode tab and a negative electrode tab, in the length direction of the battery, the positive electrode tab and the negative electrode tab are respectively led out from both ends of the battery cell body, the positive electrode tab and the negative electrode tab are respectively welded to the positive electrode column assembly and the negative electrode column assembly, the length of the battery is L, L≥400mm, the thickness of the positive electrode tab is greater than the thickness of the negative electrode tab, the width of the negative electrode tab in the width direction of the battery is W1, the width of the positive electrode tab in the width direction of the battery is W2, W1>W2; The width of the welding area between the negative electrode tab and the negative electrode column assembly in the width direction of the battery is W3, and the width of the welding area between the positive electrode tab and the positive electrode column assembly in the width direction of the battery is W4, 0.1≤(W1-W3) / (W2-W4)≤20.

2. The battery according to claim 1, characterized in that The width of the battery cell body in the width direction of the battery is W, and 0.05≤(W-W1) / (W-W2)≤0.

98.

3. The battery according to claim 2, characterized in that 10mm≤W-W1≤100mm and / or 12mm≤W-W2≤100mm.

4. The battery according to claim 1, characterized in that The width of the welding area between the negative electrode tab and the negative electrode post assembly in the width direction of the battery is W3, and the width of the welding area between the positive electrode tab and the positive electrode post assembly in the width direction of the battery is W4, 1.1≤W3 / W4≤8.

5. The battery according to claim 1, characterized in that 5mm≤W1-W3≤70mm and / or 8mm≤W2-W4≤75mm.

6. The battery according to any one of claims 1 to 5, characterized in that: The shell is provided with a liquid injection hole, and the orthographic projection of the positive electrode tab on the plane where the liquid injection hole is located at least partially overlaps with the liquid injection hole, and / or the orthographic projection of the negative electrode tab on the plane where the liquid injection hole is located at least partially overlaps with the liquid injection hole.

7. The battery according to any one of claims 1 to 5, characterized in that: The shell is provided with an injection hole, and the injection hole is arranged at one end of the positive electrode ear. The orthographic projection of the positive electrode ear on the plane where the injection hole is located does not overlap with the injection hole. The width of the battery cell body in the width direction of the battery is W, 15mm≤W-W2≤100mm, and in the length direction of the battery, the distance between the injection hole and the battery cell body is L1, 2mm≤L1≤10mm.

8. The battery according to any one of claims 1 to 5, characterized in that: A transition portion is provided between the negative electrode tab and the battery body, the radius of the transition portion is R1, and the width of the welding area between the negative electrode tab and the negative electrode column assembly in the width direction of the battery is W3,6 mm. 2 ≤R1×(W1-W3)≤350mm 2 and / or, A transition portion is provided between the positive electrode tab and the battery body, the radius of the transition portion is R2, and the width of the welding area between the positive electrode tab and the positive electrode column assembly in the width direction of the battery is W4, 10 mm 2 ≤R2×(W2-W4)≤360mm 2 .

9. The battery according to any one of claims 1 to 5, characterized in that: The shell includes a shell body and two cover plates. In the length direction of the battery, openings are provided at both ends of the shell body. The two cover plates respectively close the openings at both ends. The positive electrode column assembly and the negative electrode column assembly are respectively arranged on the two cover plates.

10. The battery according to any one of claims 1 to 5, characterized in that: The shell includes a shell body and a cover plate. In the thickness direction of the battery, an opening is provided on one side of the shell body, and the cover plate closes the opening. In the length direction of the battery, the positive electrode column assembly and the negative electrode column assembly are respectively arranged at both ends of the cover plate. In the length direction of the battery, recesses are respectively provided at both ends of the shell body, and the negative electrode tab is located in one of the recesses. In the width direction of the battery, the distance between the negative electrode tab and the side wall of the recess is D, 2mm≤D≤20mm.

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