Secondary battery

Abstract

The utility model relates to the technical field of batteries, and discloses a secondary battery, which comprises a shell, the pole group module is arranged in the shell, and the pole group module is provided with a pole lug; the cover plate body is welded with the shell, and a mounting hole is formed in the cover plate body; the pole assembly comprises a pole bottom plate and two connecting columns; the connecting column penetrates through the mounting hole and is fixedly connected with the fixing block; the pole bottom plate is welded with the pole lug; the second insulating part is arranged between the pole bottom plate and the cover plate body; the second insulating part is provided with a third end surface and a fourth end surface; the distance between the second end face of the pole bottom plate and the first end face of the cover plate body in the third direction is H1mm, H1 meets the condition that 1 / 3 * H2 < = H1 + 2 * H3 < = H2, H2 is the distance between the third end face and the fourth end face, H3 is the thickness of the tab, and the unit of H2 and H3 is mm. According to the secondary battery provided by the utility model, the energy density of the battery can be improved while the charging rate of the battery is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a secondary battery. Background Technology

[0002] The positive and negative terminals of the power battery adopt a multi-terminal design, enabling fast charging and high power output to better meet the needs of high-performance electric vehicles. How to increase the energy density of the power battery while simultaneously improving its charging rate has always been a focus of the industry. Utility Model Content

[0003] In view of this, the present invention provides a secondary battery to solve the problem of how to increase the energy density of a power battery while increasing its charging rate.

[0004] The secondary battery provided by this utility model includes:

[0005] case;

[0006] The electrode module is housed within the housing, and the electrode module has electrode tabs on one side along the third direction.

[0007] The cover plate body is welded to the shell and seals the opening of the shell. The cover plate body is provided with mounting holes that penetrate the cover plate body.

[0008] The pole assembly includes a pole base plate and two connecting posts extending from the pole base plate in a third direction; the connecting posts pass through mounting holes and are fixedly connected to a fixing block, and the pole base plate is welded to the pole lug;

[0009] The second insulating component is located between the base plate of the pole post and the cover plate body;

[0010] The cover plate body has a first end face facing the pole assembly module; the pole base plate has a second end face welded to the pole lug; the second insulating member has a third end face abutting against the first end face and a fourth end face abutting against the pole assembly module;

[0011] The distance between the second end face and the first end face along the third direction is H1 mm. H1 satisfies 1 / 3×H2≤H1+2×H3≤H2, where H2 is the distance between the third end face and the fourth end face along the third direction, and H3 is the thickness of the tab. The units of H2 and H3 are both mm.

[0012] Beneficial effects: The secondary battery provided by this utility model uses two connecting posts for each terminal assembly, and the tabs are directly welded to the side of the terminal base plate away from the connecting posts. This not only eliminates the connecting piece between the tabs and the terminal, improving the internal space utilization of the battery and thus increasing the energy density of the battery, but also reduces the local current density and internal resistance of the battery, improving the charging rate and enhancing the high-current charge and discharge performance of the battery. H1, H2, and H3 satisfy 1 / 3×H2≤H1+2×H3≤H2, which not only ensures the overcurrent of the terminal assembly and the tabs and improves the charging rate of the battery, but also improves the internal space utilization of the battery, thereby improving the energy density of the battery. In addition, it can also prevent the tabs from being inserted backward into the inside of the terminal module, preventing damage to the tabs due to compression stress.

[0013] In one optional implementation, the value of H1 is in the range of 0 ≤ H1 ≤ 2.5;

[0014] And / or, the range of H2 is 2 ≤ H2 ≤ 8;

[0015] And / or, the value range of H3 is 0.1≤H3≤2.4.

[0016] Beneficial effects: Based on satisfying 1 / 3×H2≤H1+2×H3≤H2, by further limiting the range of values ​​of H1, H2 and H3, on the one hand, the overcurrent of the terminal assembly and the tab is guaranteed, and the charging rate of the battery is improved. On the other hand, the space occupied by components such as the terminal assembly, the second insulator and the tab inside the battery can be optimized, the space utilization rate inside the battery can be improved, thereby improving the energy density of the battery. Furthermore, it can prevent the tab from being inserted backward into the inside of the electrode module, and prevent the tab from being damaged by compression force.

[0017] In one optional embodiment, the dimension of the pole base plate along the third direction is H4. When the pole base plate is an aluminum matrix base plate, H4 satisfies 1mm≤H4≤3mm; when the pole base plate is a copper matrix base plate, H4 satisfies 1mm≤H4≤2.5mm.

[0018] Beneficial effects: When the terminal base plate is an aluminum matrix base plate, H4 meets the requirement of 1mm≤H4≤3mm. When the terminal base plate is a copper matrix base plate, H4 meets the requirement of 1mm≤H4≤2.5mm. On the one hand, this avoids welding through the terminal base plate, ensuring the reliability of the welding between the terminal base plate and the tab. On the other hand, it avoids the heat from welding between the terminal base plate and the tab affecting the sealing ring, preventing the sealing ring from failing. Furthermore, it can optimize the space occupied by the terminal base plate inside the battery, improve the space utilization rate inside the battery, and help reduce battery weight and cost.

[0019] In one optional implementation, the distance between two connecting posts of the same polarity along the second direction is W1, where W1 satisfies 2mm≤W1≤30mm;

[0020] And / or, along the second direction, the minimum distance between the edge of the connecting post and the fixed block is W2, where W2 satisfies 2mm≤W2≤30mm;

[0021] And / or, the dimension of the fixing block along the first direction is L1 mm, the diameter of the connecting column is D mm, and L1 and D satisfy 1.1≤L1 / D≤5;

[0022] And / or, the dimension of the cover plate body along the first direction is L2 mm, where L2 satisfies 1.1≤L2 / L1≤5.

[0023] Beneficial effects: The distance W1 between two connecting posts of the same polarity along the second direction Y satisfies W1≥2mm, and the distance W2 between the edge of the connecting post and the fixing block satisfies W2≥2mm, thereby preventing the two connecting posts from being squeezed during riveting, avoiding cracking and deformation of the fixing block or cover plate body during riveting, and leaving appropriate space for welding the connecting post and the battery plate; in addition, W1≤30mm and W2≤30mm, thereby avoiding design redundancy and waste, and improving the mass energy density of the battery.

[0024] By satisfying L1 / D≥1.1, and L1 and L2 by satisfying L2 / L1≥1.1, we can prevent the welding heat from affecting the first insulating component during the welding process between the connecting column and the fixing block, and between the cover plate body and the periphery of the shell. This also prevents laser interference and avoids riveting cracking and deformation. At the same time, L1 / D≤5 and L2 / L1≤5 avoid design redundancy and waste, thereby improving the mass energy density of the battery.

[0025] In one alternative embodiment, the fixing block has a recessed platform formed by the side of the fixing block opposite to the cover plate body along a third direction, and the recessed platform is arranged circumferentially around the connecting column.

[0026] The connecting post has a protrusion at one end, which is furthest from the base plate of the pole post along a third direction. The protrusion extends radially from the outer circumference of the connecting post in a direction furthest from the connecting post. The protrusion abuts against the countersunk platform along a third direction. The volume of the protrusion is V1 mm. 3 ;

[0027] A positioning blind hole is provided at the end of the connecting post that is furthest from the base plate of the pole post in a third direction. The spatial volume of the positioning blind hole is V2mm. 3 V1 and V2 satisfy 1.05 ≤ V2 / V1 ≤ 1.5;

[0028] And / or, the tilt angle of the positioning blind hole is β, where β satisfies 90°≤β≤180°.

[0029] Beneficial effects: By ensuring that V1 and V2 satisfy 1.05≤V2 / V1≤1.5, and β satisfies 90°≤β≤180°, the riveting effect is ensured, the gap between the protrusion and the fixing block after riveting is reduced, and the subsequent welding of the connecting column and the fixing block is facilitated.

[0030] In one alternative embodiment, the protrusion is welded to the fixing block along a third direction away from the sinking platform.

[0031] Beneficial effects: By welding the protrusion to the fixed block along the third direction Z away from the sink, the contact resistance between the connecting column and the fixed block can be reduced, the current carrying capacity can be improved, and foreign objects can be prevented from entering the gap and the contact surface can be oxidized.

[0032] In one optional implementation, the pole group module includes two pole group units arranged in pairs along a first direction; each pole group unit is provided with two tabs of opposite polarity;

[0033] Each pole base plate is welded to the same polarity of the two pole group units.

[0034] Beneficial effects: By welding the base plate of a single terminal assembly to the tabs of two terminal units of the same polarity, and by providing two connecting posts for the terminal assembly, it is beneficial to reduce the local current density and the internal resistance of the battery, thereby improving the charging rate of the battery.

[0035] In one optional embodiment, the pole base plate and two electrodes of the same polarity are welded together to form two weld marks extending in a second direction, the distance between the two weld marks in a first direction is L2 mm; the pole base plate has a dimension of L3 mm in the first direction, and L2 and L3 satisfy 0.05≤L2 / L3≤0.95.

[0036] And / or, the dimension of the solder mark along the second direction is W3, and the dimension of the pole base plate along the second direction is W4, where W3 and W4 satisfy 0.2≤W3 / W4≤0.95.

[0037] Beneficial effects: By ensuring that L2 and L3 satisfy 0.05≤L2 / L3≤0.95, and / or W3 and W4 satisfy 0.2≤W3 / W4≤0.95, the welding effect and reliability between the pole base plate and the pole ear are guaranteed on the one hand, the current carrying capacity of the connecting post is guaranteed on the other hand, and the welding time between the pole base plate and the pole ear is avoided to ensure the welding yield between the pole base plate and the pole ear.

[0038] In one optional implementation, for the same pole assembly, the total cross-sectional area of ​​the two connecting poles is S1, and the total area of ​​the solder joint formed by the pole base plate and the two pole lugs is S2, where S1 and S2 satisfy 0.8≤S1 / S2≤2.0.

[0039] Beneficial effects: By satisfying S1 / S2≥0.8, S1 and S2 ensure the consistency of current flow; at the same time, by satisfying S1 / S2≤2.0, S1 and S2 ensure material utilization and minimize the volume and material usage of the terminal plate while ensuring the current flow capacity of the terminal assembly, thereby improving the mass energy density of the battery.

[0040] In one alternative embodiment, the cover plate body is further provided with an explosion-proof valve, which is located between the two pole post assemblies.

[0041] The second insulating member also has a fifth end face facing the electrode tab, the fifth end face and the electrode tab being spaced apart from each other along the second direction; the minimum distance between the fifth end face and the electrode tab along the second direction is W5 mm, the minimum distance between the side of the electrode tab away from the fifth end face and the explosion-proof valve along the second direction is W6 mm, and min{W5, W6} is W7.

[0042] The electrode module includes a positive electrode, a negative electrode, and a separator. The separator includes a substrate and an adhesive layer disposed on at least one surface of the substrate. The coverage of the adhesive layer is K. The secondary battery satisfies:

[0043] 90%≤K≤100%, 0<W7≤4, the pole group module is a stacked core;

[0044] Alternatively, 20% ≤ K ≤ 80%, 0 < W7 ≤ 6, and the pole group module is a stacked core.

[0045] Beneficial effects: This setting provides a certain amount of space for the tabs in the second direction Y, avoiding conflicts between the battery's internal structure and the tabs. It also makes the internal component layout of the battery more compact and reasonable, improving the internal space utilization of the battery. Furthermore, it prevents the tabs from being impacted when the explosion-proof valve is opened, thus preventing damage to the tabs and preventing short circuits inside the battery.

[0046] In one alternative implementation, the two connecting posts are eccentrically positioned on the base plate of the pole post in the second direction toward the fifth end face.

[0047] Beneficial effects: On the cover plate body, for two pole assembly with opposite polarities, the two connecting posts of each pole assembly are eccentrically set on the pole base plate along the second direction Y towards the fifth end face close to the second insulator. This not only increases the width of the circuit design in the middle of the battery pack, but also increases the misalignment space of the internal tabs along the second direction Y, thereby improving the process yield. Attached Figure Description

[0048] 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.

[0049] Figure 1 This is a perspective view of a secondary battery according to an embodiment of the present utility model;

[0050] Figure 2 for Figure 1 A top view of the secondary battery shown;

[0051] Figure 3 for Figure 2 Sectional view of section AA;

[0052] Figure 4 for Figure 3 A magnified view of a portion of point B in the middle;

[0053] Figure 5 for Figure 4 A magnified view of a portion of point C in the middle;

[0054] Figure 6 for Figure 3 A sectional view of the middle cover plate body;

[0055] Figure 7 for Figure 3 A cross-sectional view of the second insulating component;

[0056] Figure 8 for Figure 1 3D view of the center pole assembly;

[0057] Figure 9 for Figure 3 Cross-sectional view of the center pole assembly;

[0058] Figure 10 for Figure 1 3D view of the intermediate pole module;

[0059] Figure 11 for Figure 2 Top view of the mid-polarity module;

[0060] Figure 12 for Figure 1 3D view of the mid-electrode module and pole assembly;

[0061] Figure 13 for Figure 2 3D view of the mid-electrode module and pole assembly;

[0062] Figure 14 This is a cross-sectional view of a secondary battery according to an embodiment of the present invention.

[0063] Explanation of reference numerals in the attached figures:

[0064] 10. Pole assembly module; 11. Pole assembly unit; 111. Pole tab;

[0065] 20. Cover plate body; 21. Mounting hole; 22. First end face;

[0066] 30. Fixing block; 31. Recessed platform;

[0067] 40. First insulating component;

[0068] 50. Pole post assembly; 51. Pole post base plate; 511. Second end face; 512. Weld mark; 52. Connecting post; 521. Protrusion; 522. Positioning blind hole;

[0069] 60. Second insulating component; 61. Third end face; 62. Fourth end face; 63. Fifth end face;

[0070] 70. Sealing ring;

[0071] 80. Explosion-proof valve;

[0072] 90. Shell;

[0073] X—first direction; Y—second direction; Z—third direction. Detailed Implementation

[0074] 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.

[0075] The following is combined with Figures 1 to 14 The following describes embodiments of the present invention.

[0076] According to an embodiment of the present invention, a secondary battery is provided, comprising:

[0077] Casing 90;

[0078] The pole group module 10 is located inside the housing 90; please assemble it together. Figure 3 and Figure 4 As shown, the pole assembly module 10 has a pole tab 111 on one side along the third direction Z;

[0079] Cover body 20, please refer to Figure 14 As shown, the opening of housing 90 is welded to and seals the housing 90. Please refer to [link / reference]. Figure 6 As shown, the cover plate body 20 is provided with a mounting hole 21 that penetrates the cover plate body 20;

[0080] For pole assembly 50, please refer to [link / reference]. Figure 9 As shown, it includes a pole base plate 51 and two connecting posts 52 extending from the pole base plate 51 in a third direction Z; please refer to Figure 4 As shown, the connecting post 52 passes through the mounting hole 21 and is fixedly connected to the fixing block 30, and the pole base plate 51 is welded to the pole lug 111;

[0081] The second insulating element 60 is disposed between the pole base plate 51 and the cover plate body 20;

[0082] Please combine Figure 4 and Figure 6 As shown, the cover plate body 20 has a first end face 22 facing the pole assembly module 10; please refer to Figure 4 and Figure 9 As shown, the pole base plate 51 has a second end face 511 that is welded to the pole lug 111; please refer to Figure 4 and Figure 7 As shown, the second insulating member 60 has a third end face 61 that abuts against the first end face 22 and a fourth end face 62 that abuts against the pole group module 10.

[0083] The distance between the second end face 511 and the first end face 22 along the third direction Z is H1 mm. H1 satisfies 1 / 3×H2≤H1+2×H3≤H2, where H2 is the distance between the third end face 61 and the fourth end face 62 along the third direction Z, and H3 is the thickness of the tab 111. The units of H2 and H3 are both mm.

[0084] It should be noted that, in this text, "first direction X" refers to the thickness direction of the secondary battery and / or the width direction of the cover body 20; "second direction Y" refers to the width direction of the secondary battery and / or the length direction of the cover body 20; and "third direction Z" refers to the height direction of the secondary battery and / or the thickness direction of the cover body 20.

[0085] If the value of “H1+2×H3” is too small, it will not only fail to guarantee the overcurrent of the tab 111 and affect the charging rate of the battery, but also easily reduce the internal space utilization of the battery. Therefore, H1+2×H3≥1 / 3×H2 must be satisfied. If the value of “H1+2×H3” is too large, it will not only easily cause the tab 111 to be inserted upside down into the inside of the electrode module 10, but also easily cause damage to the tab 111 under compression. Therefore, H1+2×H3≤H2 must also be satisfied.

[0086] The secondary battery provided by this utility model uses two connecting posts 52 for each terminal assembly 50, and directly welds the tabs 111 to the side of the terminal base plate 51 away from the connecting posts 52. This not only eliminates the connecting piece between the tabs and the terminal, improving the internal space utilization of the battery and thus increasing the energy density of the battery, but also reduces the local current density and internal resistance of the battery, improving the charging rate and enhancing the high-current charging and discharging performance of the battery. H1, H2 and H3 satisfy 1 / 3×H2≤H1+2×H3≤H2, which not only ensures the overcurrent of the terminal assembly 50 and the tabs 111 and improves the charging rate of the battery, but also improves the internal space utilization of the battery, thereby improving the energy density of the battery. In addition, it can also prevent the tabs 111 from being inserted backward into the terminal module 10, preventing damage to the tabs 111 under compression.

[0087] Furthermore, a first insulating element 40 is provided between the fixing block 30 and the cover plate body 20; a sealing ring 70 is provided between the pole post assembly 50 and the cover plate body 20.

[0088] In some embodiments, the value of H1 is 0 ≤ H1 ≤ 2.5;

[0089] And / or, the range of H2 is 2 ≤ H2 ≤ 8;

[0090] And / or, the value range of H3 is 0.1≤H3≤2.4.

[0091] It should be noted that, please refer to Figure 4 As shown, based on satisfying 1 / 3×H2≤H1+2×H3≤H2, by further limiting the range of values ​​of H1, H2 and H3, on the one hand, the overcurrent of the terminal assembly 50 and the tab 111 is guaranteed, and the charging rate of the battery is improved. On the other hand, the space occupied by components such as the terminal assembly 50, the second insulating part 60 and the tab 111 inside the battery can be optimized, thereby improving the space utilization rate inside the battery and thus improving the energy density of the battery. Furthermore, it can prevent the tab 111 from being inserted backward into the inside of the electrode module 10, and prevent the tab 111 from being damaged by compression force.

[0092] In some embodiments, see Figure 9 As shown, the dimension of the pole base plate 51 along the third direction Z is H4. When the pole base plate 51 is an aluminum matrix base plate, H4 satisfies 1mm≤H4≤3mm; when the pole base plate 51 is a copper matrix base plate, H4 satisfies 1mm≤H4≤2.5mm.

[0093] It should be noted that if the dimension H4 of the terminal base plate 51 along the third direction Z is too small, during the welding process between the terminal base plate 51 and the tab 111, it is not only easy to weld through the terminal base plate 51, affecting the reliability of the welding between the terminal base plate 51 and the tab 111, but also the welding heat between the terminal base plate 51 and the tab 111 can easily affect the sealing ring 70, causing the sealing ring 70 to fail. Therefore, H4 needs to satisfy H4≥1mm. If the dimension H4 of the terminal base plate 51 along the third direction Z is too large, it is not only easy to increase the space occupied by the terminal base plate 51 inside the battery, reducing the space utilization rate inside the battery, but also not conducive to the weight reduction and cost reduction of the battery. Therefore, H4 also needs to satisfy: when the terminal base plate 51 is an aluminum matrix base plate, H4≤3mm; when the terminal base plate 51 is a copper matrix base plate, H4≤2.5mm.

[0094] When the terminal base plate 51 is an aluminum matrix base plate, H4 satisfies 1mm≤H4≤3mm. When the terminal base plate 51 is a copper matrix base plate, H4 satisfies 1mm≤H4≤2.5mm. On the one hand, this avoids welding through the terminal base plate 51, ensuring the reliability of the welding between the terminal base plate 51 and the tab 111. On the other hand, it avoids the heat of welding between the terminal base plate 51 and the tab 111 from affecting the sealing ring 70, preventing the sealing ring 70 from failing. Furthermore, it optimizes the space occupied by the terminal base plate 51 inside the battery, improves the space utilization rate inside the battery, and is conducive to reducing battery weight and cost.

[0095] Preferably, H4 satisfies 1.5mm≤H4≤2.0mm, wherein the dimension of the aluminum substrate along the third direction Z must be greater than or equal to the dimension of the copper substrate along the third direction Z.

[0096] In some embodiments, see Figure 2 As shown, the distance between two connecting posts 52 of the same polarity along the second direction Y is W1, and W1 satisfies 2mm≤W1≤30mm;

[0097] And / or, along the second direction Y, the minimum distance between the edge of the connecting post 52 and the fixed block 30 is W2, where W2 satisfies 2mm≤W2≤30mm;

[0098] And / or, the dimension of the fixing block 30 along the first direction X is L1 mm, see [link to relevant documentation]. Figure 9 As shown, the diameter of the connecting post 52 is D mm, and L1 and D satisfy 1.1≤L1 / D≤5;

[0099] And / or, the size of the cover plate body 20 along the first direction X is L2 mm, where L2 satisfies 1.1≤L2 / L1≤5.

[0100] The distance W1 between the two connecting posts 52 of the same polarity along the second direction Y satisfies W1≥2mm, and the distance W2 between the connecting post 52 and the edge of the fixing block 30 satisfies W2≥2mm. This prevents the two connecting posts 52 from being squeezed during riveting, avoids cracking and deformation of the fixing block 30 or the cover plate body 20 during riveting, and leaves appropriate space for welding the connecting post 52 to the battery. In addition, W1≤30mm and W2≤30mm, thereby avoiding design redundancy and waste, and improving the mass energy density of the battery.

[0101] By satisfying L1 / D≥1.1, and L1 and L2 by satisfying L2 / L1≥1.1, we can prevent the welding heat from affecting the first insulating component 40 during the welding process between the connecting column 52 and the fixing block 30 and the welding process between the cover plate body 20 and the periphery of the shell 90. This also prevents laser interference and avoids riveting cracking and deformation. At the same time, L1 / D≤5 and L2 / L1≤5 can avoid design redundancy and waste, and improve the mass energy density of the battery.

[0102] Preferably, W1 satisfies 5mm≤W1≤15mm.

[0103] In some embodiments, see Figure 5 As shown, the fixing block 30 has a recessed platform 31, which is formed by the side of the fixing block 30 away from the cover plate body 20 along the third direction Z. The recessed platform 31 is arranged circumferentially around the connecting column 52.

[0104] The connecting post 52 has a protrusion 521 at one end along the third direction Z away from the pole base plate 51. The protrusion 521 extends radially away from the outer peripheral surface of the connecting post 52. The protrusion 521 abuts against the recessed platform 31 along the third direction Z. The volume of the protrusion 521 is V1 mm. 3 ;

[0105] Please combine Figure 9 As shown, the end of the connecting post 52 furthest from the pole post base plate 51 along the third direction Z is provided with a positioning blind hole 522, and the spatial volume of the positioning blind hole 522 is V2 mm. 3 V1 and V2 satisfy 1.05 ≤ V2 / V1 ≤ 1.5;

[0106] And / or, the tilt angle of the positioning blind hole 522 is β, where β satisfies 90°≤β≤180°.

[0107] It should be noted that during the manufacturing process, the connecting post 52 passes through the mounting hole 21 and can be riveted to the fixing block 30. During this process, pressure can be applied to the end face of the positioning blind hole 522 of the connecting post 52 by the riveting tool, so that the material of the connecting post 52 flows and forms the protrusion 521 and the positioning blind hole 522. V1 and V2 satisfy 1.05≤V2 / V1≤1.5, and β satisfies 90°≤β≤180°, thereby ensuring the riveting effect, reducing the gap between the protrusion 521 and the fixing block 30 after riveting, and facilitating the subsequent welding of the connecting post 52 and the fixing block 30.

[0108] In some embodiments, the protrusion 521 is welded to the fixing block 30 on the side of the third direction Z away from the sink 31.

[0109] By welding the protrusion 521 to the fixing block 30 along the third direction Z away from the sink 31, the contact resistance between the connecting post 52 and the fixing block 30 can be reduced, the current carrying capacity can be improved, and foreign objects can be prevented from entering the gap and the contact surface can be oxidized.

[0110] In some embodiments, see Figure 10 As shown, the pole group module 10 includes two pole group units 11 arranged in pairs along the first direction X; each pole group unit 11 is provided with two tabs 111 with opposite polarities;

[0111] Please combine them together Figure 3 and Figure 12 As shown, each pole base plate 51 is welded to the same polarity tab 111 of the two pole group units 11.

[0112] By welding the base plate 51 of a single terminal assembly 50 to the tabs 111 of the same polarity of two terminal units 11, and by providing two connecting posts 52 to the terminal assembly 50, it is beneficial to reduce the local current density and the internal resistance of the battery, thereby improving the charging rate of the battery.

[0113] In some embodiments, see Figure 11 As shown, the pole base plate 51 and two pole lugs 111 of the same polarity are welded together to form two weld marks 512 extending along the second direction Y. The distance between the two weld marks 512 along the first direction X is L2 mm. The pole base plate 51 has a dimension of L3 mm along the first direction X. L2 and L3 satisfy 0.05≤L2 / L3≤0.95.

[0114] And / or, the dimension of the solder mark 512 along the second direction Y is W3, and the dimension of the pole base plate 51 along the second direction Y is W4, where W3 and W4 satisfy 0.2≤W3 / W4≤0.95.

[0115] It should be noted that the values ​​of "L2 / L3" and / or "W3 / W4" cannot be too small. Otherwise, not only will the welding effect and reliability between the base plate 51 and the tab 111 be compromised, but the local current density between the base plate 51 and the tab 111 will also be increased, reducing the current carrying capacity of the connecting post 52. Therefore, L2 / L3 ≥ 0.05 and W3 / W4 ≥ 0.2 must be met. If the values ​​of "L2 / L3" and / or "W3 / W4" are too large, it will easily lead to insufficient welding positioning dimensions and excessive welding dimensions between the base plate 51 and the tab 111, resulting in excessively long welding time and ultimately affecting the welding yield between the base plate 51 and the tab 111. Therefore, L2 / L3 ≤ 0.95 and W3 / W4 ≤ 0.95 must also be met.

[0116] By ensuring that L2 and L3 satisfy 0.05≤L2 / L3≤0.95, and / or W3 and W4 satisfy 0.2≤W3 / W4≤0.95, the welding effect and reliability between the pole base plate 51 and the pole tab 111 are guaranteed on the one hand, the current carrying capacity of the connecting post 52 is guaranteed on the other hand, and the welding time between the pole base plate 51 and the pole tab 111 is avoided to prevent excessive welding time, thus ensuring the welding yield between the pole base plate 51 and the pole tab 111.

[0117] In some embodiments, for the same pole assembly 50, the total cross-sectional area of ​​the two connecting poles 52 is S1, and the total area of ​​the solder mark 512 formed by the pole base plate 51 and the two pole ears 111 is S2, where S1 and S2 satisfy 0.8≤S1 / S2≤2.0.

[0118] S1 and S2 ensure the consistency of current flow by satisfying S1 / S2≥0.8; at the same time, S1 and S2 ensure material utilization by satisfying S1 / S2≤2.0, and minimize the volume and material usage of the terminal base plate 51 while ensuring the current flow capacity of the terminal assembly 50, thereby improving the mass energy density of the battery.

[0119] In some embodiments, see Figure 3 As shown, the cover plate body 20 is also provided with an explosion-proof valve 80, which is located between the two pole post assemblies 50;

[0120] Please see Figure 7 As shown, the second insulating member 60 also has a fifth end face 63 facing the electrode tab 111, and the fifth end face 63 and the electrode tab 111 are disposed at a distance from each other along the second direction Y; please refer to this in conjunction with... Figure 3 and Figure 4 As shown, the minimum distance between the fifth end face 63 and the tab 111 along the second direction Y is W5 mm, the minimum distance between the side of the tab 111 away from the fifth end face 63 and the explosion-proof valve 80 along the second direction Y is W6 mm, and min{W5, W6} is W7.

[0121] Electrode module 10 includes a positive electrode, a negative electrode, and a separator. The separator includes a substrate and an adhesive layer disposed on at least one surface of the substrate. The coverage of the adhesive layer is K. The secondary battery satisfies:

[0122] 90%≤K≤100%, 0<W7≤4, pole group module 10 is a stacked core;

[0123] Alternatively, 20% ≤ K ≤ 80%, 0 < W7 ≤ 6, and pole group module 10 is a stacked core.

[0124] It should be noted that "min{W5, W6} is W7" means that the smallest of the arrays W5 and W6 is W7. Since the tabs 111 are multi-layered and stacked, there is a certain degree of misalignment after the cell is formed. Therefore, a certain amount of space needs to be reserved inside the battery to accommodate the tabs 111. The secondary battery satisfies the following conditions: 90% ≤ K ≤ 100%, 0 < W7 ≤ 4, for the electrode module 10 to be a stacked core; or 20% ≤ K ≤ 80%, 0 < W7 ≤ 6, for the electrode module 10 to be a stacked core. Here, the adhesive layer coverage K refers to the coverage of the adhesive layer on the substrate surface within a 1mm × 1mm area. When 90% ≤ K ≤ 100%, the adhesive layer coverage is high, indicating that the separator is an oil-based separator; when 20% ≤ K ≤ 80%, the adhesive layer coverage is low, indicating that the separator is a water-based separator. Because the adhesive layer coverage of oil-based separators is higher than that of water-based separators, the tension uniformity of the separator bonding with the positive and negative electrode sheets is better. Therefore, after forming a core or stacked core, the electrode tab misalignment displacement using oil-based separators is smaller. When the electrode module 10 is a stacked core and the separator is an oil-based separator, the electrode tab 111 can be guaranteed not to be interfered with in the second direction Y if 0 < W7 ≤ 4. When the electrode module 10 is a stacked core and the separator is a water-based separator, W7 needs to satisfy 0 < W7 ≤ 6 to guarantee that the electrode tab 111 is not interfered with in the second direction Y. Through this design, on the one hand, a certain amount of space is reserved for the electrode tab 111 in the second direction Y to avoid conflict between the internal structure of the battery and the electrode tab 111; on the other hand, the internal component layout of the battery is more compact and reasonable, improving the internal space utilization of the battery; and furthermore, the electrode tab 111 is prevented from being impacted when the explosion-proof valve 80 is opened, preventing damage to the electrode tab 111 and preventing short circuits inside the battery.

[0125] In some embodiments, please combine Figure 4 , Figure 7 and Figure 9 As shown, the two connecting posts 52 are eccentrically positioned on the pole post base plate 51 along the second direction Y toward the direction close to the fifth end face 63.

[0126] On the cover plate body 20, for two pole post assemblies 50 with opposite polarities, the two connecting posts 52 of each pole post assembly 50 are eccentrically arranged on the pole post base plate 51 along the second direction Y toward the fifth end face 63 close to the second insulator 60. This can not only increase the width of the circuit design in the middle of the battery pack, but also increase the misalignment space of the internal electrode tabs 111 along the second direction Y, thereby improving the process yield.

[0127] Referring to Table 1 below, the charging rate and energy density of the secondary battery provided in the embodiments of this utility model are verified through several sets of test examples.

[0128] Table 1

[0129]

[0130] As can be seen from the analysis of Table 1, the secondary battery provided by this utility model uses two connecting posts for each terminal assembly and welds the tabs directly to the side of the terminal base plate away from the connecting posts. H1, H2 and H3 satisfy 1 / 3×H2≤H1+2×H3≤H2, which can not only improve the charging rate of the battery, but also improve the energy density of the battery.

[0131] 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 secondary battery, characterized in that, include: Shell (90); A pole assembly module (10) is disposed inside the housing (90), and the pole assembly module (10) has a tab (111) on one side along the third direction (Z); The cover plate body (20) is welded to the housing (90) and seals the opening of the housing (90). The cover plate body (20) is provided with a mounting hole (21) that penetrates the cover plate body (20). The pole assembly (50) includes a pole base plate (51) and two connecting posts (52) extending from the pole base plate (51) along the third direction (Z); the connecting posts (52) pass through the mounting hole (21) and are fixedly connected to the fixing block (30); the pole base plate (51) is welded to the pole tab (111). The second insulating element (60) is disposed between the pole base plate (51) and the cover plate body (20); The cover plate body (20) has a first end face (22) facing the pole assembly module (10); the pole post base plate (51) has a second end face (511) welded to the pole lug (111); the second insulating member (60) has a third end face (61) abutting against the first end face (22) and a fourth end face (62) abutting against the pole assembly module (10); The distance between the second end face (511) and the first end face (22) along the third direction (Z) is H1 mm, where H1 satisfies 1 / 3×H2≤H1+2×H3≤H2, where H2 is the distance between the third end face (61) and the fourth end face (62) along the third direction (Z), and H3 is the thickness of the tab (111). The units of H2 and H3 are both mm.

2. The secondary battery according to claim 1, characterized in that, The value range of H1 is 0 ≤ H1 ≤ 2.5; And / or, the range of H2 is 2 ≤ H2 ≤ 8; And / or, the value range of H3 is 0.1≤H3≤2.

4.

3. The secondary battery according to claim 2, characterized in that, The dimension of the pole base plate (51) along the third direction (Z) is H4. When the pole base plate (51) is an aluminum matrix base plate, H4 satisfies 1mm≤H4≤3mm; when the pole base plate (51) is a copper matrix base plate, H4 satisfies 1mm≤H4≤2.5mm.

4. The secondary battery according to claim 1, characterized in that, The distance between the two connecting posts (52) of the same polarity along the second direction (Y) is W1, where W1 satisfies 2mm≤W1≤30mm; And / or, along the second direction (Y), the minimum distance between the connecting post (52) and the edge of the fixing block (30) is W2, where W2 satisfies 2mm≤W2≤30mm; And / or, the dimension of the fixing block (30) along the first direction (X) is L1 mm, the diameter of the connecting column (52) is D mm, and L1 and D satisfy 1.1≤L1 / D≤5; And / or, the size of the cover plate body (20) along the first direction (X) is L2 mm, where L2 satisfies 1.1≤L2 / L1≤5.

5. The secondary battery according to claim 1, characterized in that, The fixing block (30) has a recessed platform (31), which is formed by the fixing block (30) being recessed along the third direction (Z) on the side away from the cover plate body (20), and the recessed platform (31) is arranged circumferentially around the connecting column (52); The connecting post (52) has a protrusion (521) at one end away from the pole base plate (51) along the third direction (Z). The protrusion (521) extends radially away from the connecting post (52) from the outer peripheral surface of the connecting post (52). The protrusion (521) abuts against the recessed platform (31) along the third direction (Z). The volume of the protrusion (521) is V1 mm. 3 ; The connecting post (52) has a positioning blind hole (522) at one end along the third direction (Z) away from the pole post base plate (51), and the spatial volume of the positioning blind hole (522) is V2 mm. 3 V1 and V2 satisfy 1.05 ≤ V2 / V1 ≤ 1.5; And / or, the tilt angle of the positioning blind hole (522) is β, where β satisfies 90°≤β≤180°.

6. The secondary battery according to claim 5, characterized in that, The protrusion (521) is welded to the fixing block (30) on the side away from the sinker (31) along the third direction (Z).

7. The secondary battery according to claim 1, characterized in that, The pole group module (10) includes two pole group units (11) arranged in pairs along a first direction (X); each pole group unit (11) is provided with two tabs (111) with opposite polarities; Each of the pole base plates (51) is welded to the tabs (111) of the same polarity of the two pole group units (11).

8. The secondary battery according to claim 7, characterized in that, The pole base plate (51) and the two pole lugs (111) of the same polarity are welded together to form two weld marks (512) extending along the second direction (Y). The distance between the two weld marks (512) along the first direction (X) is L2 mm. The dimension of the pole base plate (51) along the first direction (X) is L3 mm. L2 and L3 satisfy 0.05≤L2 / L3≤0.

95. And / or, the dimension of the solder mark (512) along the second direction (Y) is W3, and the dimension of the pole base plate (51) along the second direction (Y) is W4, where W3 and W4 satisfy 0.2≤W3 / W4≤0.

95.

9. The secondary battery according to claim 8, characterized in that, For the same pole assembly (50), the total cross-sectional area of ​​the two connecting posts (52) is S1, and the total area of ​​the solder mark (512) formed by the pole base plate (51) and the two pole ears (111) is S2. S1 and S2 satisfy 0.8≤S1 / S2≤2.

0.

10. The secondary battery according to any one of claims 1-9, characterized in that, The cover plate body (20) is also provided with an explosion-proof valve (80), which is located between the two pole post assemblies (50); The second insulating member (60) also has a fifth end face (63) facing the tab (111), the fifth end face (63) and the tab (111) being spaced apart from each other along the second direction (Y); the minimum distance between the fifth end face (63) and the tab (111) along the second direction (Y) is W5 mm, the minimum distance between the side of the tab (111) away from the fifth end face (63) and the explosion-proof valve (80) along the second direction (Y) is W6 mm, and min{W5, W6} is W7; The electrode module (10) includes a positive electrode, a negative electrode, and a separator. The separator includes a substrate and an adhesive layer disposed on at least one surface of the substrate. The coverage of the adhesive layer is K. The secondary battery satisfies: 90%≤K≤100%, 0<W7≤4, the pole group module (10) is a stacked core; Alternatively, 20% ≤ K ≤ 80%, 0 < W7 ≤ 6, the pole group module (10) is a stacked core.

11. The secondary battery according to claim 10, characterized in that, The two connecting posts (52) are eccentrically arranged on the pole base plate (51) along the second direction (Y) toward the fifth end face (63).

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