Winding type battery cell, battery, battery pack and electric equipment
By designing the tab length to increase from the inner ring to the outer ring, the problem of uneven tab lengths was solved, enabling efficient preparation without additional cutting, avoiding the generation of metal powder, and simplifying the process.
Patent Information
- Application Number
- CN202420069575.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-10
- Publication Date
- 2025-01-14
- Estimated Expiration
- 2034-01-10
AI Technical Summary
In the existing technology, the equal length of the tabs results in unevenness at the pre-welding position, requiring additional cutting, increasing the process flow, and potentially generating metal powder risk.
The design increases the length of the tabs from the inner ring to the outer ring, so that the ends of the tabs are flush after being gathered. The gradient change in the length of the tabs is achieved by laser die-cutting, avoiding additional cutting processes.
It improves preparation efficiency, avoids the generation of metal powder, simplifies the process, and reduces the investment in welding and cutting equipment.
Smart Images
Figure CN222355162U_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of new energy technology, and in particular to a wound battery cell, a battery, a battery pack and an electrical device. Background Art
[0002] According to the preparation process of the battery cell, the battery cell needs to gather and knead the tabs and pre-weld them after winding. Considering that the tabs are mostly mechanically die-cut in the related art, the tabs usually have equal lengths. When gathering, the tabs closer to the outer ring need to be bent more, and because the tabs have equal lengths, the tabs on the inner ring are longer at the pre-welding position of the tabs, while the tabs closer to the outer ring are shorter, presenting an uneven state, so the tabs at the pre-welding position need to be further cut. In this way, on the one hand, the process flow is increased, resulting in lower efficiency, and on the other hand, metal powder is easily generated during cutting, and these metal powders have the risk of causing short circuits in the battery cell if they are not removed in time. Utility Model Content
[0003] In order to overcome the problems existing in the related art, the present disclosure provides a wound battery cell, a battery, a battery pack and an electrical device.
[0004] According to a first aspect of an embodiment of the present disclosure, a wound battery cell is provided, comprising a plurality of pole tabs, wherein the lengths L of the plurality of pole tabs are configured to increase from the inner circle to the outer circle so that the ends of the folded pole tabs are flush, and the lengths L of the pole tabs satisfy:
[0005] n is an integer;
[0006] Among them, e is the length of the overlapping area after the pole ear is folded; a is the thickness of the positive electrode sheet; b is the thickness of the diaphragm; c is the thickness of the negative electrode sheet; d is the horizontal distance from the folded and deformed position of the pole ear to the overlapping area, and n is the number of layers of the battery cell.
[0007] Optionally, each circle of the wound battery cell includes two symmetrically arranged pole ears, wherein: the number of layers n of the wound battery cell is an even number, and the lengths of the two pole ears in the innermost circle are equal and the shortest; or the number of layers n of the wound battery cell is an odd number, and the pole ear in the innermost circle is the shortest.
[0008] Optionally, each circle of the wound battery cell includes one pole lug, wherein the pole lug of the innermost circle is the shortest.
[0009] Optionally, the electrode tabs include a plurality of positive electrode tabs and a plurality of negative electrode tabs, and the lengths L of the plurality of positive electrode tabs and the plurality of negative electrode tabs are configured to increase from the inner circle to the outer circle.
[0010] Optionally, the positive electrode tab and the negative electrode tab are led out from the same side of the wound battery cell or are respectively led out from two sides of the wound battery cell.
[0011] Optionally, the length difference between two adjacent pole ears is 0.2 mm-2 mm.
[0012] According to a second aspect of an embodiment of the present disclosure, there is provided a battery, comprising any one of the above-mentioned wound battery cells, wherein a plurality of the pole tabs are gathered and welded to a cover plate assembly of the battery at one time.
[0013] Optionally, the battery is a soft-pack battery.
[0014] According to a third aspect of an embodiment of the present disclosure, there is provided a battery pack comprising the above-mentioned battery.
[0015] According to a fourth aspect of an embodiment of the present disclosure, there is provided an electrical device comprising the above-mentioned battery pack.
[0016] The technical solution provided by the embodiments of the present disclosure may include the following beneficial effects: the wound battery cell provided by the present disclosure configures the lengths of the multiple pole ears to increase from the inner circle to the outer circle, so that in the process of winding up the pole ears, although the bending degree of the outer ring pole ears is greater than that of the inner ring, the length of the outer ring pole ears is also longer than that of the inner ring pole ears, so that in the process of flattening after folding, it is easy to make the ends of the pole ears in the overlapping area flush, and thus no additional cutting process is required, which is conducive to improving the preparation efficiency and there is no risk of generating metal powder. At the same time, the present disclosure makes the length of the pole ears meet That is, the length of each lug is determined based on parameters such as the thickness of the positive and negative electrodes and the separator, the length of the lug overlapping area, and the horizontal distance from the lug deformation position to the overlapping area. Compared with the method of designing the lug length based on empirical values, this method of determining the lug length is not only more precise in designing the lug length, making it easier to make the lugs level, but also can save the process of repeated trial and error based on empirical values even for battery cells with different design parameters, thereby more conveniently obtaining the required lug length.
[0017] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:
[0019] Figure 1 It is a schematic diagram of a battery cell provided in an exemplary embodiment of the present disclosure in a state where the tabs have not yet been pinched after winding.
[0020] Figure 2 It is a schematic diagram of a battery cell provided in an exemplary embodiment of the present disclosure in a state where the tabs are shaped and kneaded after winding.
[0021] Figure 3 It is a schematic diagram of the battery cell in the related art in a state where the tabs have not yet been pinched after winding.
[0022] Figure 4 It is a schematic diagram of the battery cell being shaped and kneaded after winding in the related art.
[0023] Figure 5 and Figure 6 It is a comparison chart of the related technology provided by the exemplary embodiment of the present disclosure and the optimized tab preparation process route of the present disclosure.
[0024] Description of Reference Numerals
[0025] 1-ear, 2-positive electrode sheet, 3-negative electrode sheet, 4-diaphragm. DETAILED DESCRIPTION
[0026] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.
[0027] Unless otherwise specified, directional words such as "up, down, left, right" are defined according to the directions indicated in the corresponding drawings, while "inside" and "outside" refer to the inside and outside of the outline of the corresponding component itself.
[0028] like Figure 1 and Figure 2 As shown, the present disclosure exemplarily provides a wound battery cell. Specifically, the wound battery cell includes a plurality of pole ears 1, and the lengths L of the plurality of pole ears 1 are configured to increase from the inner circle to the outer circle. Here, the length L of the pole ears 1 increases by a factor of 1. Figure 3 and Figure 4 The design of multiple tabs 1 having the same length in the related art refers to that the length L of the tab 1 satisfies:
[0029] n is an integer;
[0030] Among them, e is the length of the overlapping area after the pole ear 1 is folded; a is the thickness of the positive electrode sheet; b is the thickness of the separator; c is the thickness of the negative electrode sheet; d is the horizontal distance from the folded and deformed position of the pole ear to the overlapping area, and n is the number of layers of the battery cell.
[0031] The tabs 1 in the related art are usually cut by mechanical die cutting. Although this method has the advantage of faster die cutting speed, it can usually only die cut tabs 1 of the same length, which is specifically embodied as follows: Figure 3 The battery cell shown in FIG. 1 has multiple tabs 1 from the inner circle to the outer circle after winding, and the lengths are the same. Figure 5 and Figure 6 After the battery cell is wound, the tabs 1 need to be further gathered and kneaded and ultrasonically pre-welded, specifically from the outer ring to the inner ring. Considering that the tabs 1 of the outer ring will bend and deform during the gathering and kneading process, resulting in a shortened horizontal length, so Figure 4 As shown, in the related design with the same length of the pole lugs 1, the pole lugs 1 after pre-welding are uneven in the overlapping area. In order to ensure the quality of the final welding, it is necessary to add a pre-welding cutting step.
[0032] The wound cell provided by the present application has multiple tabs 1 whose lengths L are configured to increase from the inner circle to the outer circle, or in other words, multiple tabs 1 whose lengths are designed to change in a gradient. This tab 1 design with a gradient change can be realized by laser die cutting, that is, by using a laser die cutting path that is set in advance, which is more flexible than mechanical die cutting. It is worth noting that the limitation on the tab 1 length L here is based on the state of the cell after winding, and for the cell that has not been wound, the length L of the tab 1 is based on the state of the cell after winding. Figure 5 Taking the pole piece before winding as an example, the pole piece can be either a positive pole piece 2 or a negative pole piece 3, wherein in the length direction of the pole piece, it can include multiple groups of pole ears 1, the lengths of the multiple groups of pole ears 1 increase, and each group includes two pole ears 1 of equal length; or multiple pole ears 1 can be arranged in increments, which needs to be determined according to the actual winding method, which will be introduced in more detail later.
[0033] In this way, the length L of the multiple pole lugs 1 is configured to increase from the inner circle to the outer circle. In this way, during the process of folding the pole lugs 1 after winding, although the degree of bending of the outer ring pole lugs is greater than that of the inner ring, since the length of the outer ring pole lugs 1 is also longer than that of the inner ring pole lugs, it is easy to make the ends of the pole lugs 1 in the overlapping area flush during the flattening process after folding, and no additional cutting process is required, which is conducive to improving the preparation efficiency and there is no risk of generating metal powder. It should be noted that the overlapping area of the pole lugs 1 referred to here refers to the area where the pole lugs 1 overlap each other after folding. Specifically, Figure 2 As shown, the pole lug 1 is formed into two parts after being folded, one part is a deformation area bent toward the inner circle, and there is no overlapping part between multiple pole lugs 1 in the deformation area, and the other part is an overlapping area, and multiple pole lugs 1 overlap each other in the overlapping area.
[0034] The length L of the tab 1 of the present disclosure is configured to satisfy: n is an integer; e is the length of the overlapping area after the tab 1 is folded; a is the thickness of the positive electrode; b is the thickness of the diaphragm; c is the thickness of the negative electrode; d is the horizontal distance from the folded and deformed position of the tab to the overlapping area, and n is the number of layers of the battery cell. The deformation position of the tab 1, i.e., the position where the bending deformation occurs, is usually located at the outer edge of the diaphragm 4. It should be noted that the number of layers n of the battery cell here refers to the sum of the number of layers of the battery cell after winding and hot pressing. More specifically, Figure 2 As shown, the number of layers n of the battery cell refers to the sum of the number of layers from the inner circle to the outer circles on both sides. It should also be noted that the innermost circle is the first circle of winding, that is, the innermost circle n=1. Optionally, the length difference between two adjacent pole ears 1 is 0.2㎜-2㎜, which can achieve a better flattening effect between the pole ears. In some embodiments, each layer of the number n of layers of the battery cell includes a layer of diaphragm, a layer of positive electrode sheet, a layer of diaphragm and a layer of negative electrode sheet, and diaphragms are provided on both sides of each layer of electrode sheets, so that two electrode sheets and two electrode sheets constitute a layer of the battery cell and are wound into a battery cell, and the outermost electrode sheets are provided with diaphragms, thereby winding a complete battery cell.
[0035] As mentioned above, the tab 1 can be considered to include two parts: a deformation area and an overlap area, so the length L of the tab 1 is the length of the deformation area plus the length of the overlap area. Of course, these two parts are divided for the convenience of description, and there is no obvious boundary in actual use. Figure 2 As shown, the deformation area can be regarded as the hypotenuse of a right triangle, and its length can be calculated by the length of two right-angled sides according to the Pythagorean theorem. One of the right-angled sides is the horizontal distance d from the collapsed deformation position of the tab to the overlapping area, and the other right-angled side is the sum of the thickness a of the positive electrode sheet 2, the thickness b of the negative electrode sheet 3, and the thickness c of the separator 4 multiplied by the number of layers n of the battery cell. Then, the length e of the overlapping area after the tab is collapsed is added to obtain the length L of the tab 1.
[0036] That is, the length L of each pole lug 1 is determined according to parameters such as the thickness a of the positive electrode sheet 2, the thickness b of the negative electrode sheet 3, the thickness c of the separator 4, the length e of the pole lug overlapping area, and the horizontal distance d from the deformation position of the pole lug to the overlapping area. Compared with the method of designing the pole lug length L according to empirical values, this method of determining the pole lug length L is not only more precise in designing the pole lug length L, so that the pole lug can be more easily made flush, but also even for battery cells with different design parameters, for example, in battery cells of different specifications, having different thicknesses a, thickness b of the negative electrode sheet 3, and thickness c of the separator 4, etc., it is possible to omit the process of repeated trial and error based on empirical values, thereby more conveniently obtaining the required pole lug length L.
[0037] The technical solution provided by the embodiments of the present disclosure may include the following beneficial effects: the wound battery cell provided by the present disclosure configures the length L of the plurality of pole tabs 1 to increase from the inner circle to the outer circle, so that in the process of winding up the pole tabs 1 after winding, although the bending degree of the pole tabs 1 of the outer circle is greater than that of the inner circle, since the length L of the pole tabs 1 of the outer circle is also longer than that of the pole tabs 1 of the inner circle, it is easy to make the pole tabs 1 flush in the overlapping area during the flattening process after winding, and no additional cutting process is required, which is conducive to improving the preparation efficiency and there is no risk of generating metal powder. At the same time, the present disclosure makes the length L of the pole tab 1 meet That is, the length L of each pole lug 1 is determined according to parameters such as the thickness of the positive and negative electrode sheets and the separator, the length of the pole lug overlapping area, and the horizontal distance from the pole lug deformation position to the overlapping area. Compared with the method of designing the pole lug 1 length L according to empirical values, this method of determining the pole lug 1 length L is not only more precise in designing the pole lug 1 length L, so that the pole lug 1 can be made flat more easily, but also, even for battery cells with different design parameters, the process of repeated trial and error based on empirical values can be omitted, so that the required pole lug 1 length L can be obtained more conveniently.
[0038] Depending on the winding method of the battery cell, such as Figure 6 As shown, in some embodiments, each circle of the wound battery cell includes two symmetrically arranged pole lugs 1, that is, some embodiments are designed with a 180° pole lug structure. Specifically, when the number of layers n of the wound battery cell is an even number, the lengths L of the two pole lugs 1 of the innermost circle are equal and the shortest, and the lengths L of the other pole lugs 1 increase symmetrically from the inner circle to the outer circle in pairs; or when the number of layers n of the wound battery cell is an odd number, the innermost circle has one pole lug 1 and the pole lug 1 is the shortest, and the lengths L of the other pole lugs 1 increase symmetrically from the inner circle to the outer circle in pairs. Figure 6 Also shown is a schematic diagram of the pole piece in an unwound state, wherein, when the pole ear 1 adopts a 180° pole ear method, multiple groups of pole ears 1 are arranged along the length direction of the pole piece, the lengths of the multiple groups of pole ears 1 increase gradually, and each group includes two pole ears 1 of equal length.
[0039] In other embodiments, each circle of the wound cell includes a tab 1, that is, these embodiments are 360° tab structure designs. Among them, the tab 1 of the innermost circle is the shortest, that is, in these embodiments, the number of layers n of the non-partitioned wound cell is specifically an even number or an odd number. Different from the aforementioned 180° tab method, such as Figure 6As shown, after winding, the 180° tab method has a V-shaped length from the inner circle to the outer circle, while the 360° tab method has only one tab with increasing length from the innermost circle to one side, that is, only half of the V shape, and multiple tabs 1 increase in length along the length direction of the pole piece. This 360° tab process is conducive to avoiding the problem of TAB splitting the tab due to no pre-welding.
[0040] exist Figure 1 and Figure 2 In the illustrated embodiment, for convenience of description, only the folding and kneading of the positive electrode sheet 2 is taken as an example. However, it should be understood that the battery cell generally includes a positive electrode sheet 2 and a negative electrode sheet 3, a plurality of positive electrode ears are arranged on the positive electrode sheet 2, and a plurality of negative electrode ears are arranged on the negative electrode sheet 3. The lengths L of the plurality of positive electrode ears and the plurality of negative electrode ears are configured to increase from the inner circle to the outer circle. Furthermore, the positive electrode ear and the negative electrode ear can be led out from the same side of the wound battery cell or from both sides of the wound battery cell respectively. If the positive electrode ear and the negative electrode ear are led out from the same side of the wound battery cell, it is necessary to stagger the positive electrode ear and the negative electrode ear to avoid interference. Specifically, the positive electrode ear and the negative electrode ear can be led out from the same side of the wound battery cell or from both sides of the wound battery cell respectively, which can be configured according to the specific layout of the battery pack or the electrical equipment.
[0041] The second object of the present disclosure is to provide a battery, including any one of the above-mentioned wound cells, and having all the beneficial effects thereof. In which, after the plurality of tabs 1 are gathered together, they are welded to the cover plate assembly of the battery at one time. Specifically, Figure 5 and Figure 6 As shown, the one-time welding forming here means that after the multiple pole ears 1 are gathered, they no longer need to go through the two steps of pre-welding and cutting, but are directly welded with the cover plate assembly, which is different from the two welding processes of pre-welding before cutting and final welding with the cover plate assembly in the related art. The reason why the battery cell of the present invention can be welded and formed with the cover plate assembly in one time after the pole ears 1 are gathered is that it benefits from the design that the length of the multiple pole ears 1 increases from the inner circle to the outer circle. Due to the savings in pre-welding and cutting steps, compared with the original process route, the battery cell provided by the present invention is conducive to shortening the process, thereby reducing the investment in equipment such as welding and cutting. In addition, it should be noted that the cover plate assembly includes a cover plate and various electrical connection components arranged on the cover plate. For example, the gathered pole ears 1 are connected to the pole column through the lead-out sheet on the cover plate assembly, which will not be repeated here. Optionally, the battery can be a soft-pack battery, which does not pre-weld the pole ears compared to the square shell battery.
[0042] The third object of the present disclosure is to provide a battery pack, including the above-mentioned batteries, specifically, the batteries are grouped and loaded into a battery box.
[0043] The fourth object of the present disclosure is to provide an electrical device including the above-mentioned battery pack. The electrical device includes but is not limited to a vehicle drive motor, etc., which are not listed in detail here.
[0044] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.
[0045] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.
[0046] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.
Claims
1. A wound battery cell, comprising a plurality of tabs, characterized in that: The lengths L of the plurality of tabs are configured to increase from the inner circle to the outer circle so that the ends of the tabs after folding are flush, and the lengths L of the tabs satisfy: n is an integer; Among them, e is the length of the overlapping area after the pole ear is folded; a is the thickness of the positive electrode sheet; b is the thickness of the diaphragm; c is the thickness of the negative electrode sheet; d is the horizontal distance from the folded and deformed position of the pole ear to the overlapping area, and n is the number of layers of the battery cell.
2. The wound battery cell according to claim 1, characterized in that: Each circle of the wound battery cell includes two symmetrically arranged pole ears, wherein: the number of layers n of the wound battery cell is an even number, and the lengths of the two pole ears in the innermost circle are equal and the shortest; or the number of layers n of the wound battery cell is an odd number, and the pole ear in the innermost circle is the shortest.
3. The wound battery cell according to claim 1, characterized in that: Each circle of the wound battery cell includes a pole lug, wherein the pole lug of the innermost circle is the shortest.
4. The wound battery cell according to claim 1, characterized in that: The electrode tabs include a plurality of positive electrode tabs and a plurality of negative electrode tabs, and the lengths L of the plurality of positive electrode tabs and the plurality of negative electrode tabs are configured to increase from the inner circle to the outer circle.
5. The wound battery cell according to claim 4, characterized in that: The positive electrode tab and the negative electrode tab are led out from the same side of the wound battery cell or are respectively led out from two sides of the wound battery cell.
6. The wound battery cell according to claim 1, characterized in that: The length difference between two adjacent pole ears is 0.2mm-2mm.
7. A battery, characterized in that: The wound battery cell comprises the one described in any one of claims 1 to 6, wherein the plurality of pole tabs are gathered and welded to the cover plate assembly of the battery at one time.
8. The battery according to claim 7, characterized in that The battery is a soft pack battery.
9. A battery pack, characterized in that: A battery comprising the battery of claim 7 or 8.
10. An electrical device, characterized in that: A battery pack comprising the battery pack of claim 9.