A battery assembling process and a battery

Abstract

The application discloses a battery assembling process, comprising the following steps: S1: arranging at least two double-side tab battery cells, arranging a connecting sheet for each of the positive tab and the negative tab, and arranging a pole connecting part of the connecting sheet on a side of a tab leading end surface of a battery cell main body; stacking the battery cell main bodies to obtain a battery cell combination; S2: abutting a top cover pole of the same polarity of the positive pole and / or the negative pole with a pole connecting part of the battery cell combination, and injecting a laser beam at a space between the pole connecting part and the tab leading end surface, laser welding the abutting top cover pole and the pole connecting part to obtain a battery cell top cover combination; and S3: placing the battery cell top cover combination into a shell, and welding a top cover for connecting the shell and the battery cell top cover combination. The battery assembling process injects a laser beam at the space between the pole connecting part and the tab leading end surface to weld the pole of the top cover and the connecting sheet, so that the utilization of the internal space of the battery shell and the battery capacity are improved. The application further discloses a battery.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a battery assembly process and a battery. Background Technology

[0002] Based on the position of the tabs, batteries are classified into two types: single-sided tab and double-sided tab. In double-sided tab batteries, as disclosed in CN215600419U, the positive and negative tabs of the two cells are first stacked and then bent in a "7" shape before being connected to the terminal posts of the top cover. Figure 1 As shown. The defect of the above electrode structure is that the multi-electrode layer thickness of the two cores is relatively large, resulting in a multiple increase in the electrode height after bending, and the electrode bending height ( Figure 1 The H-type battery occupies more internal space, resulting in lower utilization of internal space and lower battery capacity. Summary of the Invention

[0003] One of the objectives of this invention is to overcome the defects in the prior art and provide a battery assembly process in which a laser beam is incident from the gap between the terminal connection and the lead-out end face of the electrode, avoiding the structure of multiple battery cell electrodes stacked and bent, reducing the internal space occupied by the electrodes in the battery casing, and improving the utilization rate of the internal space of the casing and the battery capacity.

[0004] To achieve the above-mentioned technical effects, the technical solution of the present invention is as follows: a battery assembly process, comprising the following steps: S1: Configure at least two dual-sided tab cells, with connecting tabs provided for the positive and negative tabs respectively. The pole connection parts of the connecting tabs are spaced apart on the side of the tab lead-out end face of the cell body; stack and connect the cell bodies to obtain a cell assembly. S2: The top cover pole and the pole connection part of the cell assembly are connected by the positive and / or negative poles. A laser beam is incident at the gap between the pole connection part and the lead-out end face of the electrode to laser weld the top cover pole and the pole connection part that abut against each other, so as to obtain the cell top cover assembly. S3: The battery cell and at least one top cover of the battery cell top cover assembly are inserted into the housing, and the housing and the top cover of the battery cell top cover assembly are welded together.

[0005] A preferred technical solution further includes: welding connecting pieces to the positive electrode tab and the negative electrode tab respectively, and obtaining a battery cell with a terminal connection part by means of connecting pieces with a bending structure, bending electrode tabs, or bending connecting pieces.

[0006] A preferred technical solution is that the battery cell is a multi-tab battery cell, and the battery cell bodies are stacked sequentially along the stacking direction; it also includes: gathering and fixing the tab layers of the battery cell at a first position, the first position being located on the side of the tab lead-out end face, and the first position being away from the stacking surface of the battery cell body along the stacking direction.

[0007] The preferred technical solution is that the terminal connection parts of the battery cell assembly in S2 are arranged side by side and respectively abut against the terminal of the top cover.

[0008] The preferred technical solution is that the top cover is provided with a lower plastic part, the lower plastic part is provided with a stop protrusion, the stop protrusion abuts against the lead-out end face of the electrode in S2 before laser welding, and the laser beam is incident from the lateral opening between adjacent stop protrusions or between the stop protrusion and the electrode.

[0009] A second objective of this invention is to provide a battery comprising: The battery cell is a dual-tab battery cell, consisting of the cell body, positive tab and negative tab; The housing has opposing end openings; the end openings are provided with top covers; At least two of the battery cells are stacked together in the housing; the positive and / or negative electrode tabs are respectively provided with connecting pieces, and the electrode connection portions of the connecting pieces are spaced apart on the side of the electrode lead-out end face of the battery cell body; the electrode connection portions of the battery cell are laser welded to at least one electrode of the top cover with the same polarity.

[0010] A preferred technical solution is that the positive electrode tab and / or the negative electrode tab respectively include a lead-out section and a bending section connected in sequence; the lead-out end is connected to the cell body, the bending section is bent towards one side of the cell body along the lead-out direction of the electrode tab of the cell body, and the connecting piece is connected to the bending section.

[0011] A preferred technical solution is that the battery cell is a multi-tab battery cell, and the battery cell bodies are stacked sequentially along the stacking direction; the positive electrode tabs and / or negative electrode tabs are respectively stacked and fixed at their respective first positions, the first positions are located on the front side of the battery cell body, and along the stacking direction, the first positions are away from the stacking surface of the battery cell body.

[0012] A preferred technical solution is that the pole connecting parts are arranged side by side, and the orthogonal projection of the pole connecting parts along the pole axis coincides with the pole.

[0013] A preferred technical solution is that the top cover is provided with a lower plastic part, the lower plastic part is provided with a stop protrusion, the stop protrusion abuts against the battery cell; a lateral opening is provided between the stop protrusions, the lateral opening is located on the side of the axial extension section of the electrode post, and the lateral opening is configured to accommodate the laser beam for welding the electrode post connection part and the electrode post through which it passes.

[0014] A preferred technical solution is that the width direction of the positive electrode tab and the negative electrode tab is a first direction, and the electrode post connecting part extends to the side of the corresponding positive electrode tab and the negative electrode tab in the first direction.

[0015] A preferred technical solution is that the connecting piece includes a tab connecting portion and a pole connecting portion, wherein the distance between the tab connecting portion and the corresponding tab lead-out end face is less than the distance between the pole connecting portion and the corresponding tab lead-out end face.

[0016] The advantages and beneficial effects of this invention are as follows: The battery assembly process involves irradiating a laser beam at the gap between the terminal post connection and the lead-out end face of the tab, utilizing the non-contact and long-distance characteristics of laser welding to achieve laser welding connection between the top cover terminal post and the tab connection piece. Based on the same battery cell, compared with the overall bending height of stacking and bending two or more battery cells, the distance between the electrode post connection and the electrode lead-out end face required for laser beam incident is smaller, which is conducive to further improving the utilization rate of the internal space of the battery casing and the battery capacity. This allows for the inclusion of more tab layers in a single cell, further enhancing the battery's overcurrent capability and meeting the demands of higher-current fast charging. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the tab bending structure of a dual-tab battery cell (dual-cell) in the prior art; Figure 2 This is a three-dimensional structural diagram of a single dual-sided electrode cell and connecting piece in the embodiment; Figure 3 This is a top view of the connection structure between a single dual-sided electrode cell and a connecting piece in the embodiment; Figure 4 This is the battery cell top cover assembly in the embodiment; Figure 5 yes Figure 4 A magnified view of part A in the image; Figure 6 yes Figure 4 A schematic diagram of the battery cell assembly structure corresponding to point A in the middle; Figure 7 This is a schematic diagram of the welding structure of the battery's positive terminal top cover; Figure 8 This is a schematic diagram of the welding structure of the battery negative terminal top cover; Figure 9 This is a three-dimensional structural diagram of the positive electrode top cover; Figure 10 This is a three-dimensional structural diagram of the negative electrode top cover; In the diagram: 1. Dual-sided tab cell; 11. Positive tab; 12. Negative tab; 101. Lead-out section; 102. Bending section; 13. Cell body; 131. Lead-out end face of tab; 132. Overlapping surface; 2. Connecting piece; 21. Terminal connection part; 22. Tab connection part; 3. Positive top cover; 4. Negative top cover; 5. Housing; 6. Stop protrusion; 100. Cell assembly; 200. Cell top cover assembly. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0019] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating orientation or positional relationship are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0020] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Example

[0021] like Figure 1-7 As shown, the battery assembly process in this embodiment includes the following steps: S1: Configure at least two dual-sided tab cells 1, with a connecting piece 2 for each of the positive and negative tabs 11 and 12. The terminal connection portion 21 of the connecting piece 2 is spaced apart on the side of the tab lead-out end face 131 of the cell body 13; stack and connect the cell bodies 13 to obtain a cell assembly 100. Figure 3 The structure of the cell assembly 100 corresponding to point A is as follows: Figure 4 As shown; S2: The top cover pole and the pole connection part 21 of the cell assembly 100 are connected to the positive and / or negative poles. A laser beam is incident at the interval between the pole connection part 21 and the lead-out end face 131 of the pole tab to laser weld the top cover pole and the pole connection part 21 of the positive and negative poles respectively, so as to obtain the cell top cover assembly. S3: The battery cell and at least one top cover of the battery cell top cover assembly are inserted into the housing, and the housing 5 and the top cover of the battery cell top cover assembly 200 are welded together.

[0022] Two or more battery cells can be optionally installed in the same housing 5, such as three, four, five or even more.

[0023] Taking a battery cell assembly 100 with two dual-sided tabs as an example, the first and second ends of the battery cell assembly 100 are the tab lead-out ends. Among them, the positive tab 11 of the two battery cells is located at the first end of the battery cell assembly 100, and the negative tab 12 is located at the second end of the battery cell assembly 100.

[0024] The connecting piece 2 is suitable for ternary lithium-ion batteries. The connection structure between the connecting piece 2 and the tab helps to improve the safety performance of the battery. In S1, the terminal connection part 21 of the connecting piece 2 is arranged at intervals on the side of the tab lead-out end face 131 of the cell body 13. Specifically, the terminal connection part 21 connected to the positive tab 11 is arranged on the side of the positive tab 11 lead-out end face away from the cell body 13, and the terminal connection part 21 connected to the negative tab 12 is arranged on the side of the negative tab 12 lead-out end face away from the cell body 13.

[0025] Understandably, in S2, before welding the positive electrode top cover 3 poles, the positive electrode poles abut against the pole connection portions 21 of all the positive electrode tabs in the cell assembly 100, and then the abutment area is laser welded; similarly, before welding the negative electrode top cover 4 poles, the negative electrode poles abut against the pole connection portions 21 of all the negative electrode tabs in the cell assembly 100, and then the abutment area is laser welded.

[0026] When the battery cell top cover assembly 200 obtained in S2 is connected to two top covers (positive top cover 3 and negative top cover 4 respectively), the housing 5 has opposite end openings. The welding sequence of the housing 5 and the top cover in S3 includes two types: first, the positive top cover 3 and the stacked battery cell are inserted into the housing in sequence; second, the negative top cover 4 and the stacked battery cell are inserted into the housing in sequence.

[0027] Taking the positive electrode top cover 3 and the stacked battery cell being installed into the casing in sequence as an example, S3 includes the following steps: ① For example Figure 7 , 9 As shown, the outer contour dimension of the positive electrode top cover 3 is slightly smaller than the cross-sectional dimension of the inner cavity of the housing 5; the positive electrode top cover 3 and the stacked battery cell are inserted into the housing 5 through the end opening at one end of the housing 5 in sequence until the positive electrode top cover 3 moves to the predetermined position of the end opening at the other end of the housing 5. At this time, both the positive electrode top cover 3 and the negative electrode top cover 4 meet the welding position requirements. ② Laser beam along Figure 7The laser beam is incident in the direction of arrow a, and the positive electrode top cover 3 and the housing 5 are vertically welded together. When the outer contour dimension of the negative electrode top cover 4 is the same as that of the positive electrode top cover 3, the negative electrode top cover 4 is laser vertically welded in the same way as the positive electrode top cover 3. There are no special restrictions on the welding order of the positive electrode top cover 3 and the negative electrode top cover 4 in this step.

[0028] As an alternative to welding the negative electrode top cover 4, such as Figure 8 , 10 As shown, the cover plate of the negative electrode top cover 4 includes a first stepped portion 41 and a second stepped portion 42. The second stepped portion 42 is located on the side of the first stepped portion 41 closest to the battery cell. The outer contour dimension of the second stepped portion 42 is slightly smaller than that of the first stepped portion 41. The end opening of the housing 5 is a stepped hole, which fits into the cover plate. The laser beam follows... Figure 8 The incident light is directed in the direction of the middle arrow b, and the negative electrode top cover 4 and the housing 5 are connected by side welding.

[0029] The specific steps of S3, in which the negative electrode top cover 4 and the stacked battery cell are sequentially inserted into the casing, are the same as those of the positive electrode top cover 3 and the stacked battery cell being sequentially inserted into the casing as described above.

[0030] When the cell top cover assembly 200 obtained in S2 includes only one top cover (positive top cover 3 or negative top cover 4), taking the case where only the positive top cover 3 is connected in the cell top cover assembly 200 as an example: the connection structure between the negative top cover 4 and the cell adopts any known tab and top cover connection structure. The positive top cover 3 and the negative top cover 4 are selected for vertical welding and side welding according to the size of their cross-section with the inner cavity of the housing 5. This scheme also has the effect of improving the internal space utilization and battery capacity of the housing 5, but compared with the cell top cover assembly 200 including both the positive top cover 3 and the negative top cover 4, the improvement in the internal space utilization and battery capacity of the housing 5 is smaller.

[0031] Furthermore, the top cover terminal with the same polarity contacts and abuts against the terminal connection part 21 of the cell assembly 100, which helps to reduce the stacking gap, improve the quality of laser welding, and reduce the welding defect rate.

[0032] In another preferred embodiment, the method further includes: welding the connecting piece 2 to the positive electrode tab 11 and the negative electrode tab 12 respectively, and obtaining a battery cell with a terminal connection portion 21 by means of the connecting piece 2 with the bending structure, or by bending the electrode tab or the connecting piece 2.

[0033] Preferably, the stacked structure of the connecting piece 2 and the electrode tab is ultrasonically welded. Figure 2The shaded area represents the weld point location of the ultrasonic welding. The optional bent connecting piece 2 has a first bent portion and a second bent portion. The first bent portion connects to the lead-out section of the electrode body 13, and part or all of the second bent portion serves as the electrode post connecting portion 21. The bent connecting piece 2 refers to bending the planar connecting piece 2 into a structure with the aforementioned first and second bent portions. Compared to the two bending structures for the connecting piece 2 described above, a more preferred process is: obtaining a bent section of the electrode by bending the electrode, and then ultrasonically welding the bent section to the connecting piece 2 to obtain the electrode post connecting portion 21 located on the side of the electrode lead-out end face 131. In specific operation, the connecting piece 2 can also be ultrasonically welded to the electrode first, and then the end of the electrode with the connecting piece 2 welded on it can be bent to obtain the bent section of the electrode with the connecting piece 2, that is, to obtain the electrode post connecting portion 21 located on the side of the electrode lead-out end face 131. The bent section of the tab has a large deformation allowance, which can reduce the compression of the tab root by the tab terminal connection structure during the assembly and welding process and during battery use, and reduce the risk of battery short circuit caused by tab inversion.

[0034] In another preferred embodiment, the battery cell is a multi-tab battery cell, and the battery cell body 13 is stacked sequentially along the stacking direction; it also includes: gathering and fixing the tab layers of the battery cell at a first position, the first position being located on the side of the tab lead-out end face 131, and the first position being away from the stacking surface 132 of the battery cell body 13 along the stacking direction.

[0035] When two battery cells are installed in the housing 5, the first position where the electrode layers are stacked together is as follows: Figure 6 As shown, the same-polarity tabs of the two cells are positioned far apart. The stacked tab structure effectively supports the top cover, helping to maintain the relative position of the top cover and the cells as they pass through the housing 5. This reduces the likelihood of the interaction force between the top cover and the inner surface of the housing 5 being transmitted to the tabs and the base of the tabs, causing tab deformation or inverted insertion. Furthermore, the far-away tabs are bent relative to each other, bringing the two terminal connections closer together. This increases the area of ​​the solder joints connected to the same terminal, thus increasing the current-carrying area.

[0036] When three battery cells are provided in the housing 5, the battery cell located in the middle has a relatively overlapping surface 132. At this time, the first position where the electrode layers are stacked together is located in the middle position between the two overlapping surfaces 132.

[0037] In another preferred embodiment, the terminal connection portions 21 of the cell assembly 100 in S2 are arranged side by side and all abut against the top cover terminal. Taking a two-cell battery as an example, compared with the stacked structure of the two terminal connection portions 21, the side-by-side arrangement of the terminal connection portions 21 indicates that the terminal connection portions 21 of the two cells are of equal height. This can be achieved by controlling the relative position of the cells and the bending position of the tabs, without having to consider the thickness of the terminal connection portions 21 or the influence of the stacking of the terminal connection portions 21 on the tabs of the two cells, making it more operable. Based on the same laser beam parameters and welding time, the welding of a single-layer terminal connection portion 21 to the terminal can achieve a greater penetration depth. The side-by-side arrangement of the terminal connection portions 21 also helps to evenly distribute the solder joints according to the position of the laser spot, so as to ensure that the two terminal connection portions 21 and the terminal have a nearly equal current flow area.

[0038] In another preferred embodiment, the top cover is provided with a lower plastic part, and the lower plastic part is provided with a stop protrusion 6. Before laser welding, the stop protrusion 6 abuts against the lead-out end face 131 of the electrode tab in S2. The laser beam enters from the lateral opening between adjacent stop protrusions 6 or between the stop protrusion 6 and the electrode tab.

[0039] like Figure 4 , 9 As shown in Figure 10, two stop protrusions 6 are located at both ends of the top cover. Figure 4 The gap between the two stop protrusions 6 is located on the side of the axial extension of the electrode post. The electrode tab extends away from the cell body 13, and is correspondingly located on the longer side of the electrode tab lead-out end face 131. The lead-out portion of the electrode tab is located in the above-mentioned gap opening, and a lateral opening 7 for accommodating laser incident light is sandwiched between the electrode tab and the stop protrusion 6. As an alternative to realizing the laser welding of the electrode post connection part 21 and the electrode post, or when the electrode tab completely blocks the above-mentioned gap opening, the lateral opening can also be correspondingly located on the shorter side of the electrode tab lead-out end face 131, for example, in Figure 5 A lateral opening is provided on the stop protrusion 6 corresponding to the short side of the top cover.

[0040] like Figure 2-4 As shown in Figures 7 and 8, the battery of the embodiment includes a cell and a casing 5; the cell is a dual-tab cell 1, which includes a cell body 13, a positive tab 11, and a negative tab 12; the casing 5 has opposing end openings; the end openings are provided with top covers; the cell bodies 13 of at least two cells are stacked in the casing 5; the positive tab 11 and the negative tab 12 are respectively provided with connecting pieces 2, and the terminal connection portions 21 of the connecting pieces 2 are spaced apart on the side of the tab lead-out end face 131 of the cell body 13; the terminal connection portions 21 of the cell are laser welded to the terminal of at least one top cover with the same polarity.

[0041] Furthermore, the terminal connection of the battery cell is laser-welded to the terminals of the two top covers with the same polarity. It can be understood that one of the opposite end openings of the housing 5 is provided with a positive terminal top cover 3, and the other is provided with a negative terminal top cover 4. The positive terminal top cover 3 is connected to the positive terminal tabs of two or more battery cells, and the negative terminal top cover 4 is connected to the negative terminal tabs of two or more battery cells. The two battery cells in the housing 5 are connected in parallel.

[0042] The connection structures between the positive electrode tab 11 and the positive top cover 3, and between the negative electrode tab 12 and the negative top cover 4 of the two battery cells include the following three methods: 1. The positive tabs of the two cells are connected to the positive terminal of the positive cover via their respective connecting tabs. The negative tab adopts a known tab-cover connection structure (e.g., Figure 1 As shown); 2. The negative terminals of the two cells are connected to the negative terminal post of the negative cover via their respective connecting tabs. The positive terminal uses a known terminal cover connection structure (e.g., ...). Figure 1 As shown); 3. The positive tabs of the two cells are connected to the positive terminal of the positive top cover through their respective connecting pieces, and the negative tabs are connected to the negative terminal of the negative top cover through their respective connecting pieces.

[0043] Compared to the first and second connection structures, which are alternatives, the third connection structure has higher internal space utilization and battery capacity based on the same housing.

[0044] like Figure 6 As shown, in another embodiment, the positive electrode tab 11 and the negative electrode tab 12 each include a lead-out section 101 and a bending section 102 connected in sequence; the lead-out end is connected to the cell body 13, and the bending section 102 is bent towards one side of the cell body 13 along the lead-out direction of the tab; the connecting piece 2 is connected to the bending section 102. Furthermore, the connecting piece 2 is ultrasonically welded to the bending section 102. Furthermore, the included angle between the lead-out section 101 and the bending section 102 is a right angle.

[0045] like Figure 6 As shown, in another embodiment, the battery cell is a multi-tab battery cell, with the battery cell bodies 13 stacked sequentially along the stacking direction; the positive electrode tab 11 and the negative electrode tab 12 are respectively stacked and fixed at their respective first positions, which are located on the front side of the battery cell body 13 and are away from the stacking surface 132 of the battery cell body 13 along the stacking direction. The multi-layer tabs located between the first positions and the stacking surface 132 provide diagonal support to the tab stacking structure.

[0046] like Figure 6 As shown, in another embodiment, the pole post connecting portions 21 are arranged side by side and their orthogonal projection along the pole post axis coincides with the pole post. This side-by-side arrangement helps improve laser welding efficiency and welding effect.

[0047] like Figure 5 As shown, in another embodiment, the top cover is provided with a lower plastic part, and the lower plastic part is provided with a stop protrusion 6, which abuts against the battery cell; a lateral opening 7 is provided between the stop protrusions 6, and the lateral opening 7 is located on the side of the axial extension of the electrode post, and the lateral opening 7 is configured to accommodate the welding electrode post connection part 21 and the laser beam of the electrode post through which they pass. In the combination of the top cover and the battery cell, the welding structure of the connecting piece 2 and the electrode post is maintained in the space enclosed by the lower plastic part and the end face of the battery cell. The abutment surface between the stop protrusion 6 and the battery cell also helps to disperse the resistance of the housing 5 to the top cover when the battery cell passes through the housing 5, and reduces the impact of the resistance on the electrode tab and the root of the electrode tab.

[0048] like Figure 5 , 6 As shown, in another embodiment, the width direction of the positive electrode tab 11 and the negative electrode tab 12 is the first direction, and the electrode post connection portion 21 extends to the side of the corresponding positive electrode tab 11 and negative electrode tab 12 in the first direction. The first direction is the X direction, the stacking direction of the battery cell body 13 is the Y direction, the direction perpendicular to the lead-out end face 131 of the square battery cell tab is the Z direction, the electrode post connection portion 21 is located to the side of the tab in the X direction, and the incident angle of the laser can be selected to be located parallel to the YZ plane and obliquely incident relative to the X direction.

[0049] Opposite to the above-mentioned electrode connection part 21, when the electrode connection part 21 is disposed between the positive electrode tab 11 and the negative electrode tab 12, such as Figure 6 As shown, the incident angle of the laser beam must pass through the gap between the electrode post connection 21 and the electrode lead-out end face 131 in the Z direction. The laser beam is incident at an angle relative to the X, Y and Z directions. At this time, it is necessary to pay attention to fully avoid the electrode, which significantly increases the difficulty of laser welding. Considering the welding yield, the gap between the electrode post connection 21 and the electrode lead-out end face 131 will be appropriately increased. This is not conducive to increasing the utilization rate of the internal space of the battery casing 5 and the battery capacity.

[0050] Furthermore, the connecting piece 2 includes a pole post connecting portion 21 and a tab connecting portion 22, wherein the distance between the tab connecting portion 22 and the corresponding tab lead-out end face 131 is smaller than the distance between the pole post connecting portion 21 and the corresponding tab lead-out end face 131. Optionally, the pole post connecting portion 21 has the tab connecting portion 22 bent towards the side close to the pole post.

[0051] like Figure 2 As shown, the terminal post connection portion 21 is thinner than the tab connection portion 22. Compared to the tab connection portion, the thinner terminal post connection portion also has a larger deformation allowance, which buffers vibrations during battery use and helps improve the battery safety factor.

[0052] With the direction perpendicular to the lead-out end face 131 of the square cell electrode as the Z direction, based on the same electrode and the overall height limit of the connecting mechanism of the connecting piece 2, the thinning structure of the connecting piece 2 is conducive to reducing the Z-direction height of the electrode lead-out section 101 and / or increasing the opening size in the Z direction to accommodate laser incidence, further improving the stability of the top cover assembly 200 during its passage in the housing 5, and improving the yield of the battery assembly process.

[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A battery assembly process, characterized in that, Includes the following steps: S1: Configure at least two dual-sided tab cells, with connecting tabs provided for the positive and negative tabs respectively. The pole connection parts of the connecting tabs are spaced apart on the side of the tab lead-out end face of the cell body; stack and connect the cell bodies to obtain a cell assembly. S2: The top cover pole and the pole connection part of the cell assembly are connected by the positive and / or negative poles. A laser beam is incident at the gap between the pole connection part and the lead-out end face of the electrode to laser weld the top cover pole and the pole connection part that are abutting each other, so as to obtain the cell top cover assembly. S3: The battery cell and at least one top cover of the battery cell top cover assembly are inserted into the housing, and the housing and the top cover of the battery cell top cover assembly are welded together. Also includes: The connecting pieces are welded to the positive and negative electrode tabs respectively. Through the connecting pieces with the bending structure, a battery cell with a pole connection part is obtained. The connecting piece with the bending structure has a first bending part and a second bending part. The first bending part is connected to the electrode tab from the lead-out section of the battery cell body, and the pole connection part is disposed in the second bending part. The top cover is provided with a lower plastic part, and the lower plastic part is provided with a stop protrusion. Before laser welding S2, the stop protrusion abuts against the lead-out end face of the electrode. The laser beam is incident from the lateral opening between adjacent stop protrusions or between the stop protrusion and the electrode.

2. The battery assembly process according to claim 1, characterized in that, The battery cell is a multi-tab battery cell, and the battery cell bodies are stacked sequentially along the stacking direction; it also includes: gathering and fixing the tab layers of the battery cell at a first position, the first position being located on the side of the tab lead-out end face, and the first position being away from the stacking surface of the battery cell body along the stacking direction.

3. The battery assembly process according to claim 1, characterized in that, In S2, the terminal connection parts of the battery cell assembly are arranged side by side and abut against the terminal of the top cover.

4. A battery, comprising: The battery cell is a dual-tab battery cell, consisting of the cell body, positive tab and negative tab; A housing having opposing end openings; the end openings are provided with top covers; characterized in that, based on the battery assembly process according to any one of claims 1 to 3, at least two battery cell bodies are stacked in the housing; the positive electrode tab and / or negative electrode tab are respectively provided with connecting pieces, and the terminal connection portions of the connecting pieces are spaced apart on the side of the electrode lead-out end face of the battery cell body; the terminal connection portions of the battery cell are laser welded to the terminal of at least one of the top covers with the same polarity.

5. The battery according to claim 4, characterized in that, The positive electrode tab and / or negative electrode tab each include a lead-out section and a bending section connected in sequence; the lead-out end is connected to the cell body, the bending section bends towards one side of the cell body along the lead-out direction of the electrode tab of the cell body, and the connecting piece is connected to the bending section.

6. The battery according to claim 4, characterized in that, The battery cell is a multi-tab battery cell, and the battery cell bodies are stacked sequentially along the stacking direction; the positive electrode tab and / or negative electrode tab are respectively stacked and fixed at their respective first positions, the first positions are located on the front side of the battery cell body, and along the stacking direction, the first positions are away from the stacking surface of the battery cell body.

7. The battery according to claim 4, characterized in that, The pole post connecting parts are arranged side by side, and the orthogonal projection of the pole post connecting parts along the pole post axis coincides with the pole post.

8. The battery according to claim 4, characterized in that, The top cover is provided with a lower plastic part, and the lower plastic part is provided with a stop protrusion, which abuts against the battery cell; a lateral opening is provided between the stop protrusions, and the lateral opening is located on the side of the axial extension of the electrode post, and the lateral opening is configured to accommodate the laser beam for welding the electrode post connection and the electrode post through which it passes.

9. The battery according to claim 4, characterized in that, The width direction of the positive electrode tab and the negative electrode tab is the first direction, and the electrode post connecting part extends to the side of the corresponding positive electrode tab and the negative electrode tab in the first direction.

10. The battery according to claim 9, characterized in that, The connecting piece includes a tab connection portion and a post connection portion. The distance between the tab connection portion and the corresponding tab lead-out end face is smaller than the distance between the post connection portion and the corresponding tab lead-out end face.

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