Battery assembly method and battery

Abstract

The invention belongs to the technical field of batteries, and discloses a battery assembly method and a battery, the method comprises the following steps: S1, placing a protection end plate on a first surface of a pole group provided with a tab, and enabling the tab to pass through a first through structure; s2, coating a plurality of side surfaces of the pole group and the outer side of the second surface with an insulating film which is in hot melting with the protective end plate to form a pole group unit; s3, loading the pole group unit into the cavity of the composite shell, and enabling the pole lug to penetrate through the second penetrating structure; s4, a bottom sealing plate is welded to the opening of the composite shell; s5, welding the composite pole and the composite shell; and S6, realizing current conduction between the composite pole and the tab. Current conduction is finally achieved through the tabs and the composite pole, so that the influence of other welding procedures on the connection quality of the tabs and the composite pole is avoided, and due to the fact that the tabs stretch out of the composite shell and the composite pole to achieve current conduction, occupation of the internal space of the composite shell is reduced, and the utilization rate of the space is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery assembly method and a battery. Background Art

[0002] Lithium-ion power battery is a new type of high-energy battery based on the movement of lithium ions between the positive electrode and the negative electrode. When charging, lithium ions are deintercalated from the positive electrode and embedded in the negative electrode through the electrolyte; when discharging, the opposite is true, and lithium ions are deintercalated from the negative electrode back to the positive electrode to form a current for the device to use. Because lithium-ion power batteries have the advantages of high energy, high battery voltage, wide operating temperature range, and long storage life, they are widely used in electric vehicles, energy storage systems, military equipment, etc. With continuous development, lithium-ion power batteries have derived many different types, such as blade batteries, square shell batteries or large cylindrical batteries. Among them, square shell batteries are known for their cubic or rectangular shape and solid metal shell, with high sealing, long life and good safety. With its advantages of high grouping efficiency and large single cell capacity, square shell batteries are highly competitive in the market. Square shell batteries include pole groups with pole ears on the same side, poles, cover plates, upper plastics, lower plastics, welding stations, sealing rings, and battery shells.

[0003] The traditional assembly process of square shell batteries is usually to first install the pole assembly into the battery shell, then weld the pole column to the pole ear of the corresponding polarity, then install the lower plastic and cover plate in sequence, and make a part of the pole column pass through the lower plastic and cover plate and extend out of the battery shell. After the cover plate is assembled, weld the cover plate to the battery shell, and then install the upper plastic, sealing ring and welding platform in sequence on the outer side of the cover plate corresponding to the extended part of the pole column, and complete the welding of the welding platform and the cover plate, as well as the welding of the welding platform and the pole column extending out of the cover plate, thereby completing the assembly of the square shell battery.

[0004] However, the square shell battery assembled by this method needs to complete the welding of the pole ear and the pole column first, and then complete the welding of the cover plate and the battery shell, the welding of the welding platform and the cover plate, and the welding of the welding platform and the pole column. On the one hand, the pole ear and the pole column that have been welded will be affected by adverse factors such as high temperature and vibration when the cover plate is welded to the battery shell, the welding platform is welded to the cover plate, and the welding platform is welded to the pole column, thereby reducing the welding quality between the pole column and the pole ear and reducing the product yield. On the other hand, since one side of the pole ear involves welding of the cover plate and the battery shell, welding platform and the cover plate, welding platform and the pole column, and welding of the pole ear and the pole column, a large number of welding operations are gathered on the pole ear side, resulting in the microstructure of the pole ear material being adversely changed due to the high temperature generated by a large number of welding operations, thereby affecting the electrical and mechanical properties of the pole ear itself, resulting in an increase in the resistance of the pole ear, reducing the discharge performance and cycle life of the square shell battery. Finally, since this method also requires that the pole column and the pole ear are connected inside the battery shell, the pole ear and the pole column will occupy a large space inside the battery shell, limiting the volume of the pole group, and the energy density is low. Summary of the invention

[0005] The object of the present invention is to provide a battery assembly method and a battery with high space utilization, good product quality and high energy density.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] On the one hand, a battery assembly method is provided, wherein the battery assembled by the battery assembly method comprises a composite housing, an electrode group, a bottom sealing plate, a composite electrode column and a protective end plate;

[0008] The battery assembly method comprises the following steps:

[0009] S1, the electrode group includes a first surface with a pole ear, a second surface parallel to the first surface, and multiple side surfaces perpendicular to the first surface and the second surface, the protective end plate is provided with a first penetration structure, the protective end plate is installed into the first surface of the electrode group, and the pole ear passes through the first penetration structure;

[0010] S2, coating the outer side of the electrode group with an insulating film, so that the insulating film is coated on the plurality of side surfaces and the outer side of the second surface, and hot-melting the insulating film and the protective end plate to form an electrode group unit;

[0011] S3, the composite shell is a single-side open structure with a cavity, a second through-structure for the tab to extend is provided on the wall surface opposite to the open side, and a first insulating layer for isolating the composite shell from the tab is injection-molded on the wall surface, the tab unit is installed in the cavity of the composite shell, and the tab passing through the first through-structure passes through the second through-structure;

[0012] S4, welding the bottom sealing plate to the open portion of the composite shell to seal the composite shell;

[0013] S5, a receiving groove is further provided on one side of the wall surface of the composite housing opposite to the opening, the composite pole is installed in the receiving groove, and the composite pole is welded to the composite housing;

[0014] S6. Enabling current conduction between the composite pole and the pole lug.

[0015] Optionally, in step S2, the following steps are also included:

[0016] S21, the battery further includes a bottom support plate, and the bottom support plate is pre-heat-fused at a set position of the insulating film;

[0017] S22, covering the insulating film on the plurality of side surfaces and the second surface of the electrode group, and making the bottom support plate cover the second surface of the electrode group;

[0018] S23, hot-melting the overlapping area between the insulating film and the protective end plate to form the pole group unit.

[0019] Optionally, a plurality of thermal melting points are arranged at intervals in the overlapping region between the insulating film and the protective end plate, and the distance between the boundary of each thermal melting point away from the electrode group and the boundary of the overlapping region away from the electrode group is L1, and satisfies 0.5mm≤L1≤3mm;

[0020] And / or, the distance between the boundary of each of the thermal melting points facing the electrode group and the boundary of the overlapping area facing the electrode group is L2, and satisfies 0.5mm≤L2≤3mm.

[0021] Optionally, in step S4, the following steps are also included:

[0022] S41, the bottom sealing plate and the composite shell are pre-welded and positioned at a plurality of first pre-welding points arranged at intervals;

[0023] S42, fully welding the bottom sealing plate and the composite shell.

[0024] Optionally, the composite housing comprises a housing body and the first insulating layer;

[0025] The shell body includes a first wall surface and a plurality of second wall surfaces perpendicular to the first wall surface, the plurality of second wall surfaces are arranged around the first wall surface to form a hollow shell structure with a single-side opening, the receiving groove is provided on the first wall surface, and the first wall surface is also provided with a plug-in through hole arranged in the receiving groove;

[0026] The first insulating layer is injection molded on the first wall, and includes an upper insulating portion, a lower insulating portion and a plug-in portion. The upper insulating portion is arranged on the side of the first wall facing away from the pole group and is located in the accommodating groove. The lower insulating portion is arranged on the side of the first wall facing the pole group and is located between the first wall and the protective end plate. The plug-in portion is inserted in the plug-in through hole and is used to connect the upper insulating portion and the lower insulating portion. The second through-structure penetrates the upper insulating portion, the plug-in portion and the lower insulating portion and is connected to the first through-structure.

[0027] Optionally, in step S5, the following steps are also included:

[0028] S51, a mounting groove is further provided on a side of the upper insulating portion away from the first wall surface, and the battery further comprises a connecting piece, and the connecting piece is installed in the mounting groove;

[0029] S52, bending the portion of the electrode tab extending out of the second penetrating structure, and welding the bent electrode tab to the connecting sheet;

[0030] S53, the battery further includes a sealing ring, and the sealing ring is installed in the receiving groove;

[0031] S54, placing the composite pole into the receiving groove, wherein the sealing ring is sandwiched between the composite pole and the composite housing;

[0032] S55, welding the composite pole and the composite shell.

[0033] Optionally, in step S6, the following steps are also included:

[0034] S61, a connecting boss protruding along the side of the connecting piece facing the composite pole is provided, and the composite pole is pre-welded and positioned on the connecting boss through a plurality of second pre-welding points arranged at intervals;

[0035] S62, fully welding the composite pole and the connecting boss.

[0036] Optionally, in step S55, the following steps are also included:

[0037] S551, the composite pole comprises a pole body, a welding ring and a second insulating layer for realizing an insulating connection between the pole body and the welding ring, the welding ring being pre-welded and positioned in the receiving groove through a plurality of third pre-welding points arranged at intervals;

[0038] S552, fully welding the welding ring in the receiving groove.

[0039] Optionally, in step S52, after the connecting piece is installed in the installation groove, the bent pole tab is welded to the side of the connecting piece facing the first wall, or the bent pole tab is welded to the side of the connecting piece facing the composite pole.

[0040] On the other hand, a battery is provided, wherein the battery is assembled using any of the battery assembly methods described above.

[0041] Beneficial effects of the present invention:

[0042] The present invention provides a battery assembly method, which first welds a bottom sealing plate to a composite shell, then welds a composite pole to the composite shell, and finally connects a pole ear to the composite pole to achieve current conduction, thereby avoiding the influence of other welding processes on the connection quality between the pole ear and the composite pole that have achieved current conduction on the one hand, and on the other hand, since the bottom sealing plate is welded to the open side of the composite shell away from the pole group, the amount of welding work on the pole ear side is reduced, and the influence of the high temperature generated by the welding work on the microstructure of the pole ear is reduced, thereby improving the discharge performance and cycle life of the battery. In addition, the pole ear extends out of the composite shell and the composite pole through a first penetration structure and a second penetration structure to achieve current conduction, eliminating the space occupied by the connection between the pole ear and the composite pole and the extension of the composite pole into the interior of the composite shell, thereby saving space and improving space utilization, and a protective end plate with a first penetration structure is provided on the side of the pole group where the pole ear is provided, so as to support the pole ear, avoid the pole ear from being skewed, and ensure the reliability of the structure.

[0043] The present invention also provides a battery, which is assembled by applying the above-mentioned battery assembly method, so that the volume of the electrode group can be further increased, thereby improving the energy density of the battery and increasing the power supply capacity of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a flow chart of a battery assembly method provided by the present invention;

[0045] Figure 2 is a structural exploded view of the battery provided by the present invention;

[0046] Figure 3is a partial front structural cross-sectional view of a battery provided by the present invention;

[0047] Figure 4 is a partial side structural cross-sectional view of a battery provided by the present invention;

[0048] Figure 5 It is a schematic diagram of the distribution of hot melting points of the protective end plate and the insulating film in the battery provided by the present invention;

[0049] Figure 6 yes Figure 5 A magnified view of the structure of part A;

[0050] Figure 7 This is a schematic diagram of the distribution of pre-welding points between the bottom sealing plate and the composite shell of the battery provided by the present invention;

[0051] Figure 8 It is a schematic diagram of the structure of the outer shell body of the battery provided by the present invention;

[0052] Fig. 9 It is a schematic structural diagram of the first insulating layer in the battery provided by the present invention;

[0053] Fig.10 It is a structural schematic diagram of a protective end plate in a battery provided by the present invention.

[0054] In the figure:

[0055] 1. Composite housing; 11. Housing body; 111. First wall; 112. Second wall; 113. Accommodating groove; 114. Insertion through hole; 12. First insulating layer; 121. Upper insulating part; 122. Lower insulating part; 123. Insertion part; 124. Mounting groove; 125. Second penetration structure;

[0056] 2. pole group; 21. pole ear; 22. first surface; 23. second surface; 24. side surface;

[0057] 3. Bottom sealing plate; 31. First pre-welding point;

[0058] 4. Composite pole; 41. Pole body; 42. Welding ring; 43. Second insulating layer;

[0059] 5. Protective end plate; 51. First penetration structure; 52. Shaping structure;

[0060] 6. Insulating film; 61. Thermal melting point;

[0061] 7. Bottom support plate;

[0062] 8. Connecting piece; 81. Connecting boss;

[0063] 9. Sealing ring. DETAILED DESCRIPTION

[0064] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0065] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0067] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0068] The square shell battery consists of the main components such as the electrode group with the pole ears on the same side, the pole column, the cover plate, the upper plastic, the lower plastic, the welding platform, the sealing ring and the battery shell. When the traditional method is used for assembly, the welding of the pole ear and the pole column needs to be completed first, and then the welding of the cover plate and the battery shell, the welding of the welding platform and the cover plate, and the welding of the welding platform and the pole column are completed. On the one hand, the pole ear and the pole column that have been welded will be affected by adverse factors such as high temperature and vibration when the cover plate and the battery shell are welded, the welding platform and the cover plate are welded, and the welding of the welding platform and the pole column is welded, thereby reducing the welding quality between the pole column and the pole ear and reducing the product yield. On the other hand, since one side of the pole ear involves welding of the cover plate and the battery shell, welding platform and the cover plate, welding platform and the pole column, and welding of the pole ear and the pole column, a large number of welding operations are gathered on the pole ear side, resulting in the microstructure of the pole ear material being adversely changed due to the high temperature generated by a large number of welding operations, thereby affecting the electrical and mechanical properties of the pole ear itself, resulting in an increase in the resistance of the pole ear, reducing the discharge performance and cycle life of the square shell battery. Finally, since this method also requires that the pole column and the pole ear be connected inside the battery shell, the pole ear and the pole column will occupy a large space inside the battery shell, limiting the volume of the pole group, and the energy density is low.

[0069] Therefore, in order to avoid the connection between the pole and the lug in advance, which may affect the connection quality between the pole and the lug in other subsequent processes, reduce the impact of high temperature generated by a large number of welding operations on the microstructure of the lug, and reduce additional space occupation, improve space utilization and energy density, this embodiment provides a battery assembly method, and the battery assembled by the battery assembly method includes a composite shell 1, a pole group 2, a bottom sealing plate 3, a composite pole 4 and a protective end plate 5.

[0070] like Figures 1 to 10 As shown, the battery assembly method includes the following steps:

[0071] S1, the pole group 2 includes a first surface 22 with a pole ear 21, a second surface 23 parallel to the first surface 22, and a plurality of side surfaces 24 perpendicular to the first surface 22 and the second surface 23, and a first through structure 51 is opened on the protective end plate 5, the protective end plate 5 is installed at the first surface 22 of the pole group 2, and the pole ear 21 passes through the first through structure 51;

[0072] S2, coating the outer side of the electrode group 2 with an insulating film 6, so that the insulating film 6 is coated on the outer sides of the plurality of side surfaces 24 and the second surface 23, and hot-melting the insulating film 6 and the protective end plate 5 to form an electrode group unit;

[0073] S3, the composite housing 1 is a single-side open structure with a cavity, a second through-structure 125 for the pole ear 21 to extend is provided on the wall surface opposite to the open side, and a first insulating layer 12 for isolating the composite housing 1 from the pole ear 21 is injection-molded on the wall surface, the pole group unit is installed in the cavity of the composite housing 1, and the pole ear 21 passing through the first through-structure 51 passes through the second through-structure 125;

[0074] S4, welding the bottom sealing plate 3 to the open portion of the composite shell 1 to seal the composite shell 1;

[0075] S5. A receiving groove 113 is further provided on one side of the wall of the composite housing 1 opposite to the opening, and the composite pole 4 is installed in the receiving groove 113, so that the composite pole 4 is welded to the composite housing 1;

[0076] S6, achieving current conduction between the composite pole 4 and the pole ear 21.

[0077] The battery assembly method first welds the bottom sealing plate 3 to the composite shell 1, then welds the composite pole 4 to the composite shell 1, and finally connects the pole ear 21 to the composite pole 4 to achieve current conduction, thereby avoiding the influence of other welding processes on the connection quality between the pole ear 21 and the composite pole 4 that have achieved current conduction, and on the other hand, since the bottom sealing plate 3 is welded to the open side of the composite shell 1 away from the pole group 2, the amount of welding work on the side of the pole ear 21 is reduced, and the influence of the high temperature generated by the welding work on the microstructure of the pole ear 21 is reduced, thereby improving the discharge of the battery. In addition, the pole ear 21 extends out of the composite housing 1 and the composite pole 4 through the first penetration structure 51 and the second penetration structure 125 to realize current conduction, eliminating the space occupied by the connection between the pole ear 21 and the composite pole 4 and the composite pole 4 extending into the composite housing 1, thereby saving space and improving space utilization. In addition, a protective end plate 5 with a first penetration structure 51 is provided on one side of the pole group 2 where the pole ear 21 is provided, so as to gather and support the pole ear 21, avoid the pole ear 21 from being skewed, and ensure the reliability of the structure.

[0078] Alternatively, if Figure 2 As shown, in step S2, the following steps are also included:

[0079] S21, the battery further includes a bottom support plate 7, and the bottom support plate 7 is pre-heat-fused at a set position of the insulating film 6;

[0080] S22, covering the insulating film 6 on the multiple side surfaces 24 and the second surface 23 of the electrode group 2, and making the bottom support plate 7 cover the second surface 23 of the electrode group 2;

[0081] S23, hot-melt the overlapping area between the insulating film 6 and the protective end plate 5 to form a pole group unit.

[0082] By hot-melting the bottom support plate 7 on the insulating film 6 before coating the insulating film 6, when the insulating film 6 is coated on the electrode group 2, the bottom support plate 7 can cover the second surface 23 of the electrode group 2, so that when the electrode group 2 is placed in the shell, the second surface 23 is protected by the bottom support plate 7 when the bottom sealing plate 3 and the composite shell 1 are welded, wherein the area of ​​the bottom support plate 7 is adapted to the area of ​​the second surface 23.

[0083] Alternatively, if Figure 2 , Figure 4 , Figure 6 As shown, a plurality of spaced-apart thermal melting points 61 are provided in the overlapping area between the insulating film 6 and the protective end plate 5, and the distance between the boundary of each thermal melting point 61 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 is L1, and satisfies 0.5mm≤L1≤3mm.

[0084] By setting a plurality of spaced hot melting points 61, hot melting between the insulating film 6 and the protective end plate 5 is achieved, thereby ensuring that the scope of hot melting is wide enough and the firmness of hot melting is ensured. On the other hand, compared with the full hot melting method, the hot melting area is small, thereby shortening the time required for hot melting operation and improving the efficiency of hot melting operation. At the same time, by setting the distance dimension between the boundary of each hot melting point 61 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 as L1, and limiting the distance dimension L1 between the boundary of each hot melting point 61 away from the pole group 2 and the boundary of the overlapping area away from the pole group 2 to meet 0.5mm≤L1≤3mm, it is ensured that the hot melting point 61 and the boundary of the overlapping area away from the pole group 2 maintain a suitable distance, on the one hand, avoiding the insufficient area that can be operated during hot melting due to too small a distance, and on the other hand, avoiding the loose connection of the area on the side of the hot melting point 61 away from the pole group 2 due to too large a distance.

[0085] In this embodiment, the protective end plate 5 includes a large end surface with a larger area and a small end surface with a smaller area, so the area of ​​the overlapping area formed by different end surfaces and the insulating film 6 is also different, wherein at least three hot melting points 61 arranged at intervals are arranged on the surface with a larger area, and at least one hot melting point 61 is arranged on the surface with a smaller area, wherein the shape of the hot melting point 61 can be freely set according to demand, such as circular, elliptical or polygonal, etc. wherein when there are multiple hot melting points 61, it is necessary to ensure that the multiple hot melting points 61 arranged at intervals are evenly distributed.

[0086] Among them, the distance dimension L1 between the boundary of each thermal melting point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 can be any value between 0.5mm and 3mm or a range between any two values, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.

[0087] Alternatively, if Figure 2 , Figure 4 , Figure 6 As shown, the distance between the boundary of each thermal melting point 61 facing the electrode group 2 and the boundary of the overlapping area facing the electrode group 2 is L2, and satisfies 0.5mm≤L2≤3mm.

[0088] By setting a plurality of spaced hot melt points 61, hot melting between the insulating film 6 and the protective end plate 5 is achieved, thereby ensuring that the scope of hot melting is wide enough and the firmness of hot melting is ensured, and on the other hand, compared with the full hot melting method, the hot melting operation time is short and the hot melting operation efficiency is high. At the same time, by setting the distance dimension between the boundary of each hot melting point 61 facing the pole group 2 side and the boundary of the overlapping area facing the pole group 2 side as L2, and limiting the distance dimension L2 between the boundary of each hot melting point 61 facing the pole group 2 side and the boundary of the overlapping area facing the pole group 2 side to satisfy 0.5mm≤L2≤3mm, it is ensured that the hot melting point 61 and the boundary of the overlapping area facing the pole group 2 side maintain a suitable distance, on the one hand, avoiding too small a distance, resulting in insufficient operable area during hot melting, and on the other hand, avoiding too large a distance, resulting in loose connection of the area on the side of the hot melting point 61 facing the pole group 2 side.

[0089] In this embodiment, the protective end plate 5 includes a large end surface with a larger area and a small end surface with a smaller area, so the area of ​​the overlapping area formed by different end surfaces and the insulating film 6 is also different, wherein at least three hot melting points 61 are set on the surface with a larger area, and at least one hot melting point 61 is set on the surface with a smaller area, wherein the shape of the hot melting point 61 can be freely set according to demand, such as circular, elliptical or polygonal, etc. wherein when there are multiple hot melting points 61, it is necessary to ensure that the multiple hot melting points 61 set at intervals are evenly distributed.

[0090] Among them, the distance dimension L2 between the boundary of each thermal melting point 61 toward the pole group 2 side and the boundary of the overlapping area toward the pole group 2 side can be any value between 0.5mm and 3mm or a range between any two values, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.

[0091] In this embodiment, in order to verify the influence of the distance dimension L1 and the distance dimension L2 in the battery assembly method on the quality of the assembled product, as shown in Table 1, six groups of embodiments and four groups of comparative examples are provided for verification.

[0092] Table 1

[0093]

[0094] In Example 1, the distance L1 between the boundary of the hot melt point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 0.5 mm, and the distance L2 between the boundary of the hot melt point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 0.5 mm. At this time, the battery is assembled according to the above data. After verification, the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0095] In Example 2, the distance L1 between the boundary of the hot melt point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 2 mm, and the distance L2 between the boundary of the hot melt point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 2 mm. At this time, the battery is assembled according to the above data. After verification, the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0096] In Example 3, the distance L1 between the boundary of the hot melt point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1 mm, and the distance L2 between the boundary of the hot melt point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 3 mm. At this time, the battery is assembled according to the above data. After verification, the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0097] In Example 4, the distance L1 between the boundary of the hot melting point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 3 mm, and the distance L2 between the boundary of the hot melting point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery is assembled according to the above data. After verification, the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0098] In Example 5, the distance L1 between the boundary of the hot melt point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1.5 mm, and the distance L2 between the boundary of the hot melt point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 2.5 mm. At this time, the battery is assembled according to the above data. After verification, the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0099] In Example 6, the distance L1 between the boundary of the hot melt point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 2.5 mm, and the distance L2 between the boundary of the hot melt point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1.5 mm. At this time, the battery is assembled according to the above data. After verification, the insulating film 6 is not damaged and does not fall off after the battery is disassembled.

[0100] It can be seen from Examples 1 to 6 that when the distance dimension L1 between the boundary of the hot melting point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 satisfies the range of 0.5mm≤L1≤3mm and the distance dimension L2 between the boundary of the hot melting point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 satisfies the range of 0.5mm≤L2≤3mm, the battery assembled by the battery assembly method has no damage or falling off of the insulating film 6 after disassembly of the battery, and has high product quality.

[0101] In comparative example 1, the distance L1 between the boundary of the hot melting point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 0.1 mm, and the distance L2 between the boundary of the hot melting point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery assembled according to the above data is verified to have the insulating film 6 falling off.

[0102] It can be seen from Comparative Example 1 that when the distance dimension L1 between the boundary of the hot melting point 61 away from the side of the electrode group 2 and the boundary of the overlapping area away from the side of the electrode group 2 is less than the minimum value of 0.5mm≤L1≤3mm, since the hot melting point 61 is close to the upper edge of the overlapping area of ​​the protective end plate 5, part of the hot melting point 61 exceeds the upper edge of the insulating film 6, resulting in insufficient hot melting area between the insulating film 6 and the protective end plate 5, which causes the problem of the insulating film 6 falling off, resulting in poor insulation protection performance of the assembled battery.

[0103] In comparative example 2, the distance L1 between the boundary of the hot melting point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1 mm, and the distance L2 between the boundary of the hot melting point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 0.1 mm. At this time, the battery assembled according to the above data is verified to have melt-through between the insulating film 6 and the protective end plate 5, resulting in a short circuit.

[0104] It can be seen from Comparative Example 2 that when the distance dimension L2 between the boundary of the hot melting point 61 toward the side of the electrode group 2 and the boundary of the overlapping area toward the side of the electrode group 2 is less than the minimum value of 0.5mm≤L2≤3mm, since the hot melting point 61 is close to the lower edge of the overlapping area of ​​the protective end plate 5, part of the hot melting point 61 exceeds the lower edge of the protective end plate 5, resulting in melting through between the insulating film 6 and the protective end plate 5, thereby causing a short circuit problem, resulting in poor insulation protection performance of the assembled battery.

[0105] In comparative example 3, the distance dimension L1 between the boundary of the hot melting point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 4 mm, and the distance dimension L2 between the boundary of the hot melting point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 1 mm. At this time, the battery after assembly is completed according to the above data. It is verified that the insulating film 6 is located in the area between the hot melting point 61 and the upper edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, resulting in flanging of the insulating film 6.

[0106] It can be seen from Comparative Example 3 that when the distance dimension L1 between the boundary of the hot melting point 61 away from the side of the pole group 2 and the boundary of the overlapping area away from the side of the pole group 2 is greater than the maximum value of 0.5mm≤L1≤3mm, since the hot melting point 61 is far away from the upper edge of the overlapping area of ​​the protective end plate 5, the insulating film 6 is located in the area between the hot melting point 61 and the upper edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, resulting in flanging of the insulating film 6, which does not meet the use requirements.

[0107] In comparative example 4, the distance dimension L1 between the boundary of the hot melting point 61 away from the electrode group 2 and the boundary of the overlapping area away from the electrode group 2 is set to 1 mm, and the distance dimension L2 between the boundary of the hot melting point 61 toward the electrode group 2 and the boundary of the overlapping area toward the electrode group 2 is set to 4 mm. At this time, the battery is assembled according to the above data. It is verified that the insulating film 6 is located in the area between the hot melting point 61 and the lower edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, and there is a gap between the insulating film 6 and the electrode group 2.

[0108] It can be seen from Comparative Example 4 that when the distance dimension L2 between the boundary of the hot melting point 61 toward the side of the pole group 2 and the boundary of the overlapping area toward the side of the pole group 2 is greater than the maximum value of 0.5mm≤L2≤3mm, since the hot melting point 61 is far away from the lower edge of the overlapping area of ​​the protective end plate 5, the insulating film 6 is located in the area between the hot melting point 61 and the lower edge of the overlapping area of ​​the protective end plate 5, and is not tightly connected to the protective end plate 5, thereby weakening the strength of the insulating film 6 to wrap the pole group 2, resulting in easy generation of gaps between the insulating film 6 and the pole group 2, which does not meet the use requirements.

[0109] Alternatively, if Figure 2 , Figure 7 As shown, in step S4, the following steps are also included:

[0110] S41, the bottom sealing plate 3 and the composite shell 1 are pre-welded and positioned at a plurality of first pre-welding points 31 arranged at intervals;

[0111] S42, fully welding the bottom sealing plate 3 and the composite shell 1.

[0112] By pre-welding the bottom sealing plate 3 and the composite shell 1 using a plurality of first pre-welding points 31 arranged at intervals, it is ensured that the relative positions of the bottom sealing plate 3 and the composite shell 1 are positioned before full welding. Even if the initial positioning is incorrect, it is convenient to separate and reposition the two, thereby achieving recycling and reducing the scrap rate of the product.

[0113] In this embodiment, since the bottom sealing plate 3 includes a large end surface with a larger area and a small end surface with a smaller area, the areas of the overlapping regions formed by different end surfaces and the composite shell 1 are also different, wherein at least three first pre-welding positions 31 are set on the surface with a larger area, preferably five, and at least one first pre-welding position 31 is set on the surface with a smaller area, preferably three, wherein the shape of the first pre-welding position 31 can be freely set according to demand, such as circular, elliptical or polygonal. Wherein, when there are multiple first pre-welding positions 31, it is necessary to ensure that the multiple first pre-welding positions 31 arranged at intervals are evenly distributed.

[0114] Alternatively, if Figure 2 , Figure 4 , Figure 8 , Fig. 9 As shown, the composite housing 1 includes a housing body 11 and a first insulating layer 12. The housing body 11 includes a first wall 111 and a plurality of second walls 112 perpendicular to the first wall 111. The plurality of second walls 112 are arranged around the first wall 111 to form a hollow housing structure with a single side opening. A receiving groove 113 is provided on the first wall 111. The first wall 111 is further provided with a plug-in through hole 114 arranged in the receiving groove 113. The first insulating layer 12 is injection molded on the first wall 111 and includes an upper insulating portion 121. , a lower insulating portion 122 and a plug-in portion 123, the upper insulating portion 121 is arranged on the side of the first wall 111 away from the pole group 2, and is located in the accommodating groove 113, the lower insulating portion 122 is arranged on the side of the first wall 111 facing the pole group 2, and is located between the first wall 111 and the protective end plate 5, the plug-in portion 123 is inserted in the plug-in through hole 114, and is used to connect the upper insulating portion 121 and the lower insulating portion 122, the second penetrating structure 125 penetrates the upper insulating portion 121, the plug-in portion 123 and the lower insulating portion 122 and is connected with the first penetrating structure 51.

[0115] By injection molding the first insulating layer 12 on the first wall 111 of the shell body 11, the first insulating layer 12 cooperates with the protective end plate 5 to achieve double insulation protection, thereby improving the safety and protection of the structure. In addition, by providing the first insulating layer 12 composed of an upper insulating portion 121, a lower insulating portion 122 and a plug-in portion 123, the upper insulating portion 121 is arranged on the side of the first wall 111 of the shell body 11 away from the pole group 2, the lower insulating portion 122 is arranged on the side of the first wall 111 of the shell body 11 facing the pole group 2, and the plug-in portion 123 is inserted into the plug-in through hole. 114, and the second penetrating structure 125 penetrates the upper insulating portion 121, the plug-in portion 123 and the lower insulating portion 122 to be connected with the first penetrating structure 51, so that the first insulating layer 12 is used to insulate and protect both sides of the first wall 111 of the shell body 11 and the inside of the plug-in hole 114, and isolates the pole ear 21 from the first wall 111 of the shell body 11, so as to avoid direct contact between the pole ear 21 and the first wall 111 of the shell body 11 when passing through the first wall 111 of the shell body 11, resulting in a short circuit, thereby ensuring safety and protection.

[0116] In this embodiment, the housing body 11 is an aluminum shell, and the first insulating layer 12 is a plastic part directly molded on the first wall 111 of the housing body 11 by an injection molding process. Compared with the traditional cover assembly, the separate lower insulating part is eliminated, thereby reducing the number of parts and simplifying the assembly process. In addition, in this embodiment, the upper insulating part 121, the plug-in part 123 and the lower insulating part 122 are an integrated structural part formed simultaneously by an injection molding process. In other embodiments, the upper insulating part 121, the plug-in part 123 and the lower insulating part 122 can also be separately injection molded and then plugged into each other, so that the first insulating layer 12 is a split structural part.

[0117] Alternatively, if Figure 2 , Figure 8 , Fig. 9 , Fig.10 As shown, in step S5, the following steps are also included:

[0118] S51, a mounting groove 124 is further provided on a side of the upper insulating portion 121 away from the first wall surface 111, and the battery further comprises a connecting piece 8, and the connecting piece 8 is installed in the mounting groove 124;

[0119] S52, bending the portion of the electrode tab 21 extending out of the second penetrating structure 125, and welding the bent electrode tab 21 to the connecting piece 8;

[0120] S53, the battery further includes a sealing ring 9, and the sealing ring 9 is installed in the receiving groove 113;

[0121] S54, the composite pole 4 is placed in the receiving groove 113, and the sealing ring 9 is sandwiched between the composite pole 4 and the composite housing 1;

[0122] S55, welding the composite pole 4 and the composite shell 1.

[0123] By providing the connecting piece 8 and welding the pole lug 21 to the connecting piece 8, the position of the pole lug 21 can be fixed in advance by using the connecting piece 8, thereby ensuring the accuracy of the position of the pole lug 21 during subsequent operations and avoiding the pole lug 21 from moving and affecting the conduction effect of the current between the pole lug 21 and the composite pole 4.

[0124] Among them, the electrode group 2 includes a positive electrode ear and a negative electrode ear located on the same side, so two connecting pieces 8, two sealing rings 9 and two composite poles 4 are correspondingly provided. When assembling the connecting piece 8, the sealing ring 9 and the composite pole 4, the positive electrode ear and the negative electrode ear can be assembled with the connecting piece 8, the sealing ring 9 and the composite pole 4 at the same time, or the connecting piece 8, the sealing ring 9 and the composite pole 4 on the positive electrode ear side can be assembled first, and after the assembly is completed, the connecting piece 8, the sealing ring 9 and the composite pole 4 on the negative electrode ear side can be assembled. In this embodiment, the simultaneous assembly method is adopted to reduce the time required for assembly and improve the efficiency of assembly.

[0125] Optionally, in step S6, the following steps are also included:

[0126] S61, a connecting boss 81 is provided on one side of the connecting piece 8 facing the composite pole 4 and protrudes along the composite pole 4, and the composite pole 4 is pre-welded and positioned on the connecting boss 81 through a plurality of second pre-welding points arranged at intervals;

[0127] S62, fully welding the composite pole 4 and the connecting boss 81.

[0128] By providing a connecting boss 81 on the side of the connecting piece 8 facing the composite pole 4, it is convenient to weld the connecting piece 8 to the composite pole 4. The size and shape of the connecting boss 81 can be freely set according to demand, and it is sufficient to ensure that there is a sufficient welding area between the connecting boss 81 and the composite pole 4. In this embodiment, the connecting boss 81 is a truncated cone.

[0129] In addition, the composite pole 4 is first pre-welded to the connecting boss 81 through a plurality of second pre-welding points arranged at intervals, so as to ensure that the relative position between the composite pole 4 and the connecting boss 81 is preliminarily positioned before full welding, thereby ensuring the accuracy of the position of the two after welding during full welding, ensuring the welding quality, and even if the initial positioning is incorrect, it is convenient to separate and reposition the two, realize recycling, and reduce the scrap rate of the product.

[0130] Alternatively, if Figure 2 , Figure 4 As shown, in step S55, the following steps are also included:

[0131] S551, the composite pole 4 includes a pole body 41, a welding ring 42 and a second insulating layer 43 for achieving an insulating connection between the pole body 41 and the welding ring 42, and the welding ring 42 is pre-welded and positioned in the receiving groove 113 through a plurality of third pre-welding points arranged at intervals;

[0132] S552 , fully weld the welding ring 42 into the receiving groove 113 .

[0133] First, the welding ring 42 is pre-welded in the installation groove 124 through a plurality of third pre-welding points arranged at intervals, so as to ensure that the relative position of the welding ring 42 in the installation groove 124 is positioned before full welding. Even if the initial positioning is wrong, it is convenient to separate and reposition the two, realize recycling, and reduce the scrap rate of the product. The number, size and shape of the third pre-welding points used to realize the pre-welding of the welding ring 42 can be freely set according to actual needs.

[0134] Optionally, in step S52, after the connecting piece 8 is installed in the installation groove 124, the bent pole tab 21 is welded to the side of the connecting piece 8 facing the first wall 111, or the bent pole tab 21 is welded to the side of the connecting piece 8 facing the composite pole 4. In order to adapt to various different working environments, it is convenient to perform welding operations on the bent pole tab 21 and the connecting piece 8. In this embodiment, the bent pole tab 21 is welded to the side of the connecting piece 8 facing the composite pole 4.

[0135] Alternatively, if Figure 4 As shown, a shaping structure 52 corresponding to the first through structure 51 is provided on the side of the protective end plate 5 facing the pole group 2, and the shaping structure 52 is a trumpet-shaped structure whose opening gradually decreases in the direction away from the pole group 2, so that in step S1, the multiple converged pole ears 21 on the pole group 2 are better supported and fixed, the convergence state of the pole ears 21 is improved, and the problem of short circuit inside the battery due to poor convergence effect of the pole ears 21 is avoided.

[0136] In this embodiment, if Figure 2 As shown, a battery is also provided, which is assembled by the above-mentioned battery assembly method. The battery is assembled by applying the above-mentioned battery assembly method, so that the volume of the electrode group 2 is further increased, thereby improving the energy density of the battery and increasing the power supply capacity of the battery.

[0137] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A battery assembly method, characterized in that: The battery assembled by the battery assembly method comprises a composite shell, an electrode group, a bottom sealing plate, a composite electrode column and a protective end plate; The battery assembly method comprises the following steps: S1, the electrode group includes a first surface with a pole ear, a second surface parallel to the first surface, and multiple side surfaces perpendicular to the first surface and the second surface, the protective end plate is provided with a first penetration structure, the protective end plate is installed into the first surface of the electrode group, and the pole ear passes through the first penetration structure; S2, coating the outer side of the electrode group with an insulating film, so that the insulating film is coated on the plurality of side surfaces and the outer side of the second surface, and hot-melting the insulating film and the protective end plate to form an electrode group unit; S3, the composite shell is a single-side open structure with a cavity, a second through-structure for the tab to extend is provided on the wall surface opposite to the open side, and a first insulating layer for isolating the composite shell from the tab is injection-molded on the wall surface, the tab unit is installed in the cavity of the composite shell, and the tab passing through the first through-structure passes through the second through-structure; S4, welding the bottom sealing plate to the open portion of the composite shell to seal the composite shell; S5, a receiving groove is further provided on one side of the wall surface of the composite housing opposite to the opening, the composite pole is installed in the receiving groove, and the composite pole is welded to the composite housing; S6. Enabling current conduction between the composite pole and the pole lug.

2. The battery assembly method according to claim 1, characterized in that: In step S2, the following steps are also included: S21, the battery further includes a bottom support plate, and the bottom support plate is pre-heat-fused at a set position of the insulating film; S22, covering the insulating film on the plurality of side surfaces and the second surface of the electrode group, and making the bottom support plate cover the second surface of the electrode group; S23, hot-melting the overlapping area between the insulating film and the protective end plate to form the pole group unit.

3. The battery assembly method according to claim 2, characterized in that: A plurality of thermal melting points are arranged at intervals in the overlapping region between the insulating film and the protective end plate, and the distance between the boundary of each thermal melting point away from the electrode group and the boundary of the overlapping region away from the electrode group is L1, and satisfies 0.5mm≤L1≤3mm; And / or, the distance between the boundary of each of the thermal melting points facing the electrode group and the boundary of the overlapping area facing the electrode group is L2, and satisfies 0.5mm≤L2≤3mm.

4. The battery assembly method according to claim 1, characterized in that: In step S4, the following steps are also included: S41, the bottom sealing plate and the composite shell are pre-welded and positioned at a plurality of first pre-welding points arranged at intervals; S42, fully welding the bottom sealing plate and the composite shell.

5. The battery assembly method according to claim 1, characterized in that: The composite housing comprises a housing body and the first insulating layer; The shell body includes a first wall surface and a plurality of second wall surfaces perpendicular to the first wall surface, the plurality of second wall surfaces are arranged around the first wall surface to form a hollow shell structure with a single-side opening, the receiving groove is provided on the first wall surface, and the first wall surface is also provided with a plug-in through hole arranged in the receiving groove; The first insulating layer is injection molded on the first wall, and includes an upper insulating portion, a lower insulating portion and a plug-in portion. The upper insulating portion is arranged on the side of the first wall facing away from the pole group and is located in the accommodating groove. The lower insulating portion is arranged on the side of the first wall facing the pole group and is located between the first wall and the protective end plate. The plug-in portion is inserted in the plug-in through hole and is used to connect the upper insulating portion and the lower insulating portion. The second through-structure penetrates the upper insulating portion, the plug-in portion and the lower insulating portion and is connected with the first through-structure.

6. The battery assembly method according to claim 5, characterized in that: In step S5, the following steps are also included: S51, a mounting groove is further provided on a side of the upper insulating portion away from the first wall surface, and the battery further comprises a connecting piece, and the connecting piece is installed in the mounting groove; S52, welding the bent electrode tab to the connecting sheet; S53, the battery further includes a sealing ring, and the sealing ring is installed in the receiving groove; S54, placing the composite pole into the receiving groove, wherein the sealing ring is sandwiched between the composite pole and the composite housing; S55, welding the composite pole and the composite shell.

7. The battery assembly method according to claim 6, characterized in that: In step S6, the following steps are also included: S61, a connecting boss protruding along the side of the connecting piece facing the composite pole is provided, and the composite pole is pre-welded and positioned on the connecting boss through a plurality of second pre-welding points arranged at intervals; S62, fully welding the composite pole and the connecting boss.

8. The battery assembly method according to claim 6, characterized in that: In step S55, the following steps are also included: S551, the composite pole comprises a pole body, a welding ring and a second insulating layer for realizing an insulating connection between the pole body and the welding ring, the welding ring being pre-welded and positioned in the receiving groove through a plurality of third pre-welding points arranged at intervals; S552, fully welding the welding ring in the receiving groove.

9. The battery assembly method according to claim 6, characterized in that: In step S52, after the connecting piece is installed in the installation groove, the bent pole tab is welded to the side of the connecting piece facing the first wall surface, or the bent pole tab is welded to the side of the connecting piece facing the composite pole.

10. A battery, characterized in that The battery is assembled using the battery assembly method according to any one of claims 1 to 9.

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