Pole group and battery cell
By setting a specific ratio of first and second welding areas on the tab bundle, the problems of poor tab bundle convergence and tearing are solved, and the welding strength and electrical performance of the battery cell are improved.
Patent Information
- Application Number
- CN202423261881.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2026-01-23
- Estimated Expiration
- 2034-12-27
AI Technical Summary
In existing technologies, the tab bundles have poor gathering effect in the battery cell, and they are prone to tearing after being welded to the connecting pieces, which affects the performance of the battery cell.
A first welding area and a second welding area are provided on the tab bundle. The first welding area extends along the length direction of the tab bundle, and the length-to-width ratio is 0.5≤L1/L≤1 and 0.5≤W1/W≤1. The second welding area partially overlaps with the first welding area and is used to gather the tabs and weld them to the connecting piece. The spacing is D1≥2mm and D3≥0.5mm. The number of electrode pieces is 2≤N≤100.
It improves the gathering effect of the tab bundle, prevents tearing, enhances the welding strength between the tab and the connecting piece, and improves the electrical performance and safety of the battery cell.
Smart Images
Figure CN223828673U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to power battery technical field, especially relates to a pole group, simultaneously, the utility model discloses a kind of battery cell with the pole group. BACKGROUND
[0002] In prior art, the cover plate of battery cell is connected with shell by welding, and forms internal space for accommodating pole group, and the pole group (composed of positive and negative pole piece and diaphragm alternately) has pole lug bundle, the pole lug bundle is first ultrasonic welded with connecting piece, then the connecting piece is laser welded with top cover, and finally the whole battery cell is made.
[0003] The positive and negative pole piece and diaphragm are alternately stacked, and the pole lug on the top of the pole piece is also stacked, the stacked pole lug is pre-ultrasonic welded, then ultrasonic welded with the connecting piece, the connecting piece is laser welded with the top cover, the connecting piece and the pole lug are bent synchronously, and finally the cover plate is laser welded with the shell. After the pole lug bundle and the connecting piece are ultrasonic welded, the pole lug bundle is also prone to tearing, thereby affecting the performance of the battery cell. SUMMARY
[0004] Therefore, the utility model aims at providing a pole group to improve the folding effect of the pole lug bundle and prevent the pole lug bundle from tearing after being welded with the connecting piece.
[0005] To achieve the above-mentioned purpose, the technical scheme of the utility model is as follows:
[0006] A pole group comprises a pole group body and a pole lug bundle arranged at the end of the pole group body.
[0007] The pole lug bundle is rectangular, and a first welding area is arranged on the pole lug bundle, the first welding area is used for welding and folding together the plurality of stacked pole lugs, and the first welding area extends along the length direction of the pole lug bundle.
[0008] The ratio of the length L1 of the first welding area to the length L of the pole lug bundle satisfies 0.5≤L1 / L≤1, and / or the ratio of the width W1 of the first welding area to the width W of the pole lug bundle satisfies 0.5≤W1 / W≤1.
[0009] Further, the distance D1 between the first welding area and the root of the pole lug bundle satisfies D1≥2mm.
[0010] Further, a second welding area is arranged on the pole lug bundle opposite to the pole group body, and the second welding area is used for welding and connecting with the connecting piece.
[0011] The second welding area has a coinciding part arranged partially coinciding with the first welding area.
[0012] Further, a width D2 of the coinciding part in the width direction of the tab bundle satisfies: D2 >= 1mm.
[0013] Further, the second welding area is two arranged spaced along the length direction of the tab bundle.
[0014] A spacing D3 between one end of each of the second welding area facing away from each other and the edge of the same side of the tab bundle satisfies: D3 >= 0.5mm.
[0015] Further, the first welding area is located in the middle of the length direction and / or the width direction of the tab bundle.
[0016] Further, the number N of pole pieces in the pole group body satisfies: 2 <= N <= 100.
[0017] Compared with the prior art, the utility model has the following advantages:
[0018] The pole group has the first welding area arranged on the tab bundle for welding and folding together the stacked tabs, which is beneficial to improve the folding effect of the tab bundle, and the length L1 of the first welding area and the length L of the tab bundle, the width W1 of the first welding area and the width W of the tab bundle, which are beneficial to meet the tab pre-welding requirement and prevent the tab bundle from tearing after being welded with the connecting piece, thereby improving the performance of the battery cell.
[0019] In addition, the spacing range between the first welding area and the root of the tab bundle is arranged to reserve a position for the tooling, thereby preventing the pole group body from being affected during the welding process. The second welding area and the first welding area partially form the coinciding part arranged coinciding, which is beneficial to realize the welding of the tab bundle and the connecting piece and prevent the tab bundle from tearing. The width range of the coinciding part in the width direction of the tab bundle is beneficial to ensure the connection effect of the tab bundle and the connecting piece.
[0020] In addition, by arranging two second welding areas, the welding strength between the connecting piece and the tab bundle is further improved, and the spacing range between the second welding area and the edge of the tab bundle is arranged to improve the welding effect between the connecting piece and the tab bundle. The first welding area is located in the middle of the tab bundle, which is beneficial to improve the folding effect of the tab bundle. The number of pole pieces in the pole group body is arranged to facilitate the arrangement and meet the use requirements of different battery cells.
[0021] In addition, another purpose of the utility model is to provide a battery cell comprising the pole group.
[0022] The electric core improves the connecting effect between the tab bundle and the connecting sheet, and improves the electrical performance of the electric core. BRIEF DESCRIPTION OF DRAWINGS
[0023] The accompanying drawings, which form a part of this description, are included to provide a further understanding of the application. The embodiments of the application and its
[0024] Fig. 1 The structure schematic view of the pole group is described in the embodiment of the application.
[0025] Fig. 2 The structure schematic view of the pole group is described in the embodiment of the application.
[0026] Fig. 3 The structure schematic view of the pole group is described in the embodiment of the application.
[0027] BRIEF DESCRIPTION OF DRAWINGS
[0028] 1, pole group body; 2, tab bundle; 3, first welding area; 4, second welding area; 5, overlapping part. DETAILED DESCRIPTION
[0029] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict.
[0030] In the description of the application, it should be noted that if the terms indicating the orientation or position relationship such as "upper", "lower", "inner", "back" appear, they are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as limiting the application. The device or element must have a specific orientation, a specific orientation and operation, so it cannot be understood as a limitation of the application. In addition, if the terms "first", "second" appear, they are only for the purpose of description, and cannot be understood as indicating or implying relative importance.
[0031] The application will be described in detail below with reference to the drawings and in combination with the embodiments.
[0032] The embodiment relates to a pole group, to solve the problem that the tab bundle 2 on the pole group in the prior art has poor folding effect and is prone to tearing after being welded with a connecting sheet.
[0033] In terms of overall structure, the pole piece includes a pole group body 1 and a pole tab bundle 2 arranged at the end of the pole group body 1. The pole tab bundle 2 is rectangular, and the pole tab bundle 2 is provided with a first welding area 3 for welding and gathering the stacked multiple pole tabs together, and the first welding area 3 is arranged along the length direction of the pole tab bundle 2. Wherein, the ratio of the length L1 of the first welding area 3 to the length L of the pole tab bundle 2 satisfies: 0.5≤L1 / L≤1; and / or, the ratio of the width W1 of the first welding area 3 to the width W of the pole tab bundle 2 satisfies: 0.5≤W1 / W≤1.
[0034] The pole group described in the embodiment is provided with the first welding area 3 on the pole tab bundle 2 for welding and gathering the stacked pole tabs together, which is conducive to improving the gathering effect of the pole tab bundle 2. By setting the range of the ratio of the length L1 of the first welding area 3 to the length L of the pole tab bundle 2 and the range of the ratio of the width W1 of the first welding area 3 to the width W of the pole tab bundle 2, the pole tab pre-welding requirement can be met, and the tearing of the pole tab bundle 2 after welding with the connecting piece can be prevented, thereby improving the performance of the battery cell.
[0035] Based on the overall introduction as above, an exemplary structure of the pole group described in the embodiment is shown in Figs. 1 to 3 The pole tab bundle 2 can be located at one end of the pole group body 1, or at both ends of the pole group body 1, which can be determined according to the needs in specific implementation. As a preferred embodiment, the pole group body 1 is rectangular, and the pole tab bundle 2 is arranged along the width direction of the pole group body 1. Wherein, the length direction and the width direction of the pole tab bundle 2 refer to those shown in Fig. 3
[0036] As a preferred embodiment, the first welding area 3 is located at the middle part of the length direction and the width direction of the pole tab bundle 2. This is conducive to improving the strength and gathering effect of the multiple pole tabs in the welded state, thereby improving the reliability of the multiple pole tabs in the welded state. In specific implementation, the pole tab bundle 2 is ultrasonically welded at the first welding area 3. Of course, the position of the first welding area 3 can also be set only at the middle part of the length direction or the width direction of the pole tab bundle 2.
[0037] In the embodiment, the ratio of the length L1 of the first welding area 3 to the length L of the pole tab bundle 2 satisfies: 0.5≤L1 / L≤1. In specific implementation, L1 / L can be 0.5, 0.6, 0.7, 0.8, 0.9 or 1. In this way, the length of the first welding area 3 accounts for more than half of the length of the pole tab bundle 2, thereby enabling the stacked multiple pole tabs to have better connection strength in the length of the pole tab bundle 2, so as to ensure the effect of the pole tab bundle 2 in the gathered state, so that the pole tabs are not easy to disperse and have better gathering effect.
[0038] Furthermore, the ratio of the width W1 of the first welding area 3 to the width W of the tab bundle 2 satisfies: 0.5 ≤ W1 / W ≤ 1. This ensures that the width of the first welding area 3 accounts for more than half of the total width of the tab bundle 2, and also facilitates better connection strength of the stacked tabs across the width of the tab bundle 2. This ensures the effectiveness of the tab bundle 2 in the folded state, making the tabs less prone to dispersion and thus maintaining a good hand-holding effect. In specific implementations, W1 / W can be 0.5, 0.6, 0.7, 0.8, 0.9, or 1.
[0039] When L1 / L is less than 0.5, the welding strength of multiple tabs is insufficient, resulting in poor convergence of the tab bundle 2. Consequently, during welding of the tab bundle 2 and the connecting piece, tearing of the tab bundle 2 is likely to occur, affecting the electrical performance of the battery cell. The first welding area 3 is relatively short. When the battery cell is subjected to external mechanical stress (such as vibration or bending), the stress per unit length is relatively high due to the shorter length of the first welding area 3. This may make the tab bundle 2 weld joint more prone to loosening or solder joint detachment.
[0040] When W1 / W is less than 0.5, the width of the first welding area 3 is relatively narrow. When subjected to mechanical force perpendicular to the width direction (such as extrusion), the stress concentration of the narrower first welding area 3 is relatively high when subjected to the same external force, which may make the first welding area 3 more prone to cracks or damage.
[0041] In a preferred embodiment, the distance D1 between the first welding area 3 and the root of the electrode bundle 2 satisfies: D1 ≥ 2 mm. This distance D1 is a reserved position for the tooling, thus helping to avoid affecting the electrode assembly body 1 during the welding process. Specifically, the distance D1 between the first welding area 3 and the root of the electrode bundle 2 can be 2 mm, 3 mm, 3.5 mm, or 4 mm, etc.
[0042] In this embodiment, as Fig. 3 As shown, the tab bundle 2 is provided with a second welding area 4 disposed opposite to the electrode assembly body 1. The second welding area 4 is used to weld and connect with the connecting piece. The second welding area 4 has an overlapping portion 5 that partially overlaps with the first welding area 3. The overlapping portion 5 formed by the second welding area 4 and the first welding area 3 facilitates the welding of the tab bundle 2 to the connecting piece and helps prevent tearing of the tab bundle 2.
[0043] Specifically, the larger overlap portion 5 increases the cross-sectional area of the current transmission path, and reduces the resistance. This helps to reduce the Joule heat loss of the tab bundle 2 during operation, reduces the risk of performance degradation caused by heating, and enables the battery cell to charge and discharge more efficiently. Conversely, if the overlap portion 5 is small, the cross-sectional area of the conductive path is relatively small, and the resistance increases. In the case of large current charging and discharging, it may cause local overheating of the tab bundle 2, affecting the performance and safety of the battery cell.
[0044] The larger overlap portion 5 can enhance the welding strength of the tab bundle 2. The overlap portion 5 in the embodiment is equivalent to increasing the bonding area between the connecting sheet and the tab bundle 2. According to the bonding strength theory in material mechanics, the greater the bonding area, the greater the shear force and tensile force it can withstand. During the assembly process of the battery cell and subsequent use, the tab bundle 2 will be subjected to various mechanical stresses, such as vibration, extrusion, etc. A large enough overlap portion 5 can better ensure the stability of the connection between the connecting sheet and the tab bundle 2, reducing the possibility of mechanical failure such as loosening and falling off at the welding site.
[0045] A smaller overlap portion 5 may not have sufficient mechanical strength at the welding site. For example, in the case of severe vibration of the battery cell, such as during transportation of mobile electronic devices or driving of cars on bumpy roads, the tab bundle 2 with a small overlap portion 5 may cause the connecting sheet and the tab bundle 2 to separate, resulting in an instantaneous increase in the internal resistance of the battery cell, or even a short circuit, making the battery cell unable to work normally.
[0046] Furthermore, a larger overlap portion 5 is beneficial to reducing the contact resistance and thus reducing the electrochemical polarization. In the electrochemical process of the battery cell, electrode reactions need to occur at the interface between the electrode and the electrolyte, and the size of the contact resistance will affect the rate of electrode reactions. When the overlap portion 5 is large, good electrical conductivity can promote the progress of electrode reactions and improve the charging and discharging efficiency of the battery cell. For example, in a lithium-ion battery, a reasonable size of the overlap portion 5 of the tab bundle 2 can ensure smoother migration of lithium ions between the electrode and the electrolyte, improving the capacity utilization rate of the battery cell.
[0047] A too small overlap portion 5 may cause poor contact and excessive local current density. In an electrochemical system, excessive local current density may trigger a series of side reactions, such as decomposition of the electrolyte and dissolution of the electrode material. These side reactions will consume the active materials of the battery cell, reducing the cycle life and capacity of the battery cell.
[0048] For example, Fig. 3As shown in the diagram, as a preferred structural example, there are two second welding regions 4 spaced apart along the length of the tab bundle 2. Compared to a single welding region, having two spaced-apart second welding regions 4 provides more conductive paths, and the two spaced-apart second welding regions 4 also makes the current distribution more uniform. If there is only one second welding region 4, the current may concentrate near that region, resulting in excessively high local current density. Two second welding regions 4 can guide the current to be distributed more evenly along the length of the tab bundle 2, reducing local overheating and electrochemical polarization, thereby improving the charge-discharge efficiency and cycle life of the battery cell.
[0049] Furthermore, from a mechanical stability perspective, the two spaced-apart second welding areas 4 enhance the connection strength between the tab bundle 2 and the connecting piece. When the battery cell is subjected to external mechanical stress, such as vibration, bending, or compression, the two second welding areas 4 can share the mechanical force.
[0050] In this embodiment, as Fig. 3 As shown, the width D2 of the overlapping portion 5 in the width direction of the tab bundle 2 satisfies: D2 ≥ 1 mm. This ensures a sufficient conductive cross-sectional area and provides enough welding area to enhance the welding strength between the connecting piece and the tab bundle 2. During the assembly process of the battery cell and subsequent use, the overlapping portion 5 will be subjected to various mechanical stresses, such as vibration, tension, and compression. Sufficient width allows the weld joint of the overlapping portion 5 to better withstand these mechanical forces, reducing the possibility of cracks, loosening, or detachment at the weld point. In specific implementations, the width D2 can be, for example, 1 mm, 1.5 mm, 2 mm, or 3 mm.
[0051] In addition, still refer to Fig. 3 As shown, the distance D3 between the opposite end of each second welding area 4 and the edge of the same-side tab bundle 2 satisfies: D3 ≥ 0.5 mm. This effectively prevents the edge of the second welding area 4 from being too close to the edge of the tab bundle 2, thus avoiding the risk of short circuits. It also helps maintain the mechanical integrity of the tab bundle 2 and reduces the interference of edge effects on the electrochemical process. It should be noted that a scheme with only one second welding area 4 is also feasible, as long as the connection requirements of the connecting piece are met.
[0052] In addition, in this embodiment, the number N of the electrode plates in the electrode assembly body 1 satisfies: 2≤N≤100. For example, the number of electrode plates can be 2, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100, etc. In specific implementation, the number of electrode plates can also be determined according to the requirements.
[0053] The pole group in the embodiment is beneficial to improving the folding effect of the tab bundle 2 and the welding effect of the tab bundle 2 and the connecting piece, thereby improving the safety of the battery cell.
[0054] In addition, the embodiment also relates to a battery cell comprising the pole group as described above.
[0055] The battery cell described in the embodiment is beneficial to improving the safety and electrical performance of the battery cell by arranging the pole group as described above.
[0056] The above merely provides the preferred embodiments of the present application, but is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1.A jelly-roll, characterized in that: it comprises a jelly-roll body and a tab bundle arranged at an end of the jelly-roll body; the tab bundle is rectangular, and a first welding area is arranged on the tab bundle, the first welding area being used for welding a plurality of stacked tabs together, and the first welding area is arranged along a length direction of the tab bundle; a ratio of a length L1 of the first welding area to a length L of the tab bundle satisfies: 0.5≤L1 / L≤1; and / or, a ratio of a width W1 of the first welding area to a width W of the tab bundle satisfies: 0.5≤W1 / W≤1. 2.The jelly-roll according to claim 1, characterized in that: a distance D1 between the first welding area and a root of the tab bundle satisfies: D1≥2mm. 3.The jelly-roll according to claim 1, characterized in that: a second welding area is arranged on the tab bundle opposite to the jelly-roll body, and the second welding area is used for welding a connecting piece; the second welding area has a coinciding part which is partially coincided with the first welding area. 4.The jelly-roll according to claim 3, characterized in that: a width D2 of the coinciding part in a width direction of the tab bundle satisfies: D2≥1mm. 5.The jelly-roll according to claim 3, characterized in that: the second welding area is two which are arranged at intervals along the length direction of the tab bundle; a distance D3 between an end of each of the second welding areas which is away from each other and a same-side edge of the tab bundle satisfies: D3≥0.5mm. 6.The jelly-roll according to claim 1, characterized in that: the first welding area is located at a middle part of the length direction and / or the width direction of the tab bundle. 7.The jelly-roll according to any one of claims 1 to 6, characterized in that: a number N of tabs in the jelly-roll body satisfies: 2≤N≤100. 8.An electric cell, characterized in that: it comprises the jelly-roll according to any one of claims 1 to 7.