Winding battery cell and battery with same

Abstract

The utility model provides a winding battery cell. The winding battery cell comprises a body and an ending part, wherein the body comprises a positive plate, a negative plate and a diaphragm, the positive plate, the diaphragm and the negative plate are laminated and are wound along the winding direction to form the body, a positive tab is arranged on the positive plate, and a negative tab is arranged on the negative plate. The tail end of at least one of the positive plate, the diaphragm and the negative plate is connected with an ending part, the ending part wraps the body, meanwhile, the ending part is provided with at least one inflection part, the inflection part is formed by inflecting the ending part along the winding direction, and the inflection part is suitable for being straightened along the winding direction when the volume of the body is increased. According to the winding battery cell disclosed by the embodiment of the utility model, the inflection part is arranged at the ending part, and the inflection part can be straightened along the winding direction under the action of internal stress generated in an electrochemical cycle process of the winding battery cell, so that the internal stress of the winding battery cell can be reduced, the probability of breakage of a pole piece is reduced, and the service life of the winding battery cell is prolonged. And therefore, the problem of pole piece breakage of the wound battery cell is not easy to occur.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a wound battery cell and a battery having the same. Background Technology

[0002] During electrochemical cycling, the insertion and extraction of lithium ions in the wound cell of a wound battery causes changes in the volume and size of the electrode material, which in turn alters the internal stress of the wound cell. This internal stress can cause the electrode sheets of the wound cell to break and lead to a short circuit in the battery. Utility Model Content

[0003] This utility model provides a wound battery cell to solve the problem in related technologies where the electrodes of wound battery cells are prone to breakage under varying internal stress.

[0004] The wound battery cell of this utility model embodiment includes:

[0005] The body comprises a positive electrode, a negative electrode, and a separator, wherein the positive electrode, the separator, and the negative electrode are stacked and wound along a winding direction to form the body.

[0006] The positive electrode plate is provided with a positive electrode tab, and the negative electrode plate is provided with a negative electrode tab;

[0007] The tail section is connected to the tail end of at least one of the positive electrode, the separator, and the negative electrode, and wraps around the body;

[0008] The tail portion is provided with at least one fold-back portion, which is formed by folding the tail portion back along the winding direction. The fold-back portion is adapted to be straightened along the winding direction when the volume of the body increases.

[0009] The wound battery cell of this utility model has a fold-back section at the end. Under the action of the internal stress generated during the electrochemical cycle of the wound battery cell, the fold-back section can be straightened along the winding direction, thereby reducing the internal stress of the wound battery cell and reducing the probability of electrode breakage. This makes the wound battery cell less prone to electrode breakage.

[0010] Therefore, the wound battery cell of this utility model embodiment has the characteristic that the electrode sheets are not easily broken.

[0011] In some embodiments, in the width direction of the wound cell, the folded portion is misaligned with the positive and negative tabs; and / or,

[0012] In the thickness direction of the wound cell, at least one of the folded portions is positioned opposite to the positive tab or the negative tab.

[0013] In some embodiments, in the width direction of the wound battery cell, the fold-back portion is disposed between the positive electrode tab and the negative electrode tab.

[0014] At least one of the said folded portions is disposed between the positive electrode tab and the negative electrode tab; and / or,

[0015] At least one of the said folded portions is opposite to the positive electrode tab or the negative electrode tab; and / or,

[0016] At least one of the folded portions is located between the side of the positive electrode tab opposite to the negative electrode tab and the arcuate area of ​​the body; and / or,

[0017] At least one of the folded portions is located between the side of the negative electrode ear away from the positive electrode ear and the arcuate area of ​​the body.

[0018] In some embodiments, the body has a thickness reduction region, the thickness of which is less than the thickness of other parts of the body, and the folded portion is disposed in the thickness reduction region.

[0019] In some embodiments, the wound cell further includes a finishing tape, the tail end of which is connected to the outermost ring of the body via the finishing tape.

[0020] In some embodiments, the number of the folds is 1-6.

[0021] In some embodiments, the fold-back portion includes at least two or more even-numbered fold-back angles.

[0022] In some embodiments, the number of folding angles of the folded portion is an even number between 2 and 10.

[0023] In some embodiments, the fold-back length 'a' of the fold-back portion in the length direction of the tail portion is 0.5-50 mm.

[0024] In some embodiments, the terminal portion connected to the tail end of the positive electrode sheet is a positive electrode terminal portion, which is a foil integrally formed with the current collector of the positive electrode sheet; and / or,

[0025] The terminal portion connected to the tail end of the negative electrode sheet is the negative electrode terminal portion, which is a foil integrally formed with the current collector of the negative electrode sheet; and / or,

[0026] The tail section connected to the tail end of the diaphragm is the diaphragm tail section, and the diaphragm tail section is integrally formed with the diaphragm.

[0027] This utility model embodiment also provides a battery.

[0028] The battery of this utility model embodiment includes the wound cell described in the above embodiment. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the wound battery cell according to an embodiment of the present invention;

[0031] Figure 2 This is a partial structural schematic diagram of the wound battery cell according to an embodiment of the present invention;

[0032] Figure 3 This is a partial structural diagram of the tail section of the wound battery cell according to an embodiment of the present invention;

[0033] Figure 4 This is another structural schematic diagram of the wound battery cell according to an embodiment of the present invention.

[0034] In the picture:

[0035] 100. Winded battery cells;

[0036] 1. Body; 101. Positive electrode plate; 1011. Positive electrode tab; 102. Negative electrode plate; 1021. Negative electrode tab; 103. Separator;

[0037] 2. Finishing part; 201. Fold-back part; 2011. Fold-back angle;

[0038] 3. Finishing tape. Detailed Implementation

[0039] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0040] In the description of this utility model, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model 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 utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0041] In the description of this utility model, it should 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 a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal encapsulation of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0042] To address the problem that the electrodes of the wound battery cell 100 are prone to breakage under varying internal stress in related technologies, this utility model provides a wound battery cell 100.

[0043] The wound battery cell 100 of this utility model embodiment includes a body 1 and a tail portion 2.

[0044] The body 1 includes a positive electrode 101, a negative electrode 102 and a separator 103. The positive electrode 101, the separator 103 and the negative electrode 102 are stacked and wound along the winding direction to form the body 1. The positive electrode 101 is provided with a positive electrode tab 1011 and the negative electrode 102 is provided with a negative electrode tab 1021.

[0045] At least one of the positive electrode 101, the separator 103 and the negative electrode 102 has a tail end connected to a tail portion 2. The tail portion 2 wraps around the body 1. At the same time, the tail portion 2 is provided with at least one folded portion 201. The folded portion 201 is formed by folding the tail portion 2 back along the winding direction. The folded portion 201 is adapted to be straightened along the winding direction when the volume of the body 1 increases.

[0046] The wound battery cell 100 of this utility model has a fold-back portion 201 provided at the end 2. Under the action of the internal stress generated during the electrochemical cycle of the wound battery cell 100, the fold-back portion 201 can be straightened along the winding direction, thereby reducing the internal stress of the wound battery cell 100 and reducing the probability of electrode breakage. In this way, the wound battery cell 100 is less prone to electrode breakage.

[0047] Therefore, the wound battery cell 100 of this utility model embodiment has the characteristic that the electrode sheets are not prone to breakage.

[0048] The following is in conjunction with the appendix Figure 1-4 The following describes the wound battery cell 100 of this utility model embodiment.

[0049] like Figure 1 As shown, the wound battery cell 100 of this utility model embodiment includes a body 1 and a tail portion 2.

[0050] The body 1 includes a positive electrode 101, a negative electrode 102 and a separator 103. The positive electrode 101, the separator 103 and the negative electrode 102 are stacked and wound along the winding direction to form the body 1. The positive electrode 101 is provided with a positive electrode tab 1011 and the negative electrode 102 is provided with a negative electrode tab 1021.

[0051] At least one of the positive electrode 101, the separator 103, and the negative electrode 102 has a tail end connected to a tail portion 2. That is, the tail end of the positive electrode 101 can be connected to a tail portion 2, the tail end of the separator 103 can be connected to a tail portion 2, the tail end of the negative electrode 102 can be connected to a tail portion 2, the tail ends of both the positive electrode 101 and the negative electrode 102 can be connected to a tail portion 2, the tail ends of both the positive electrode 101 and the separator 103 can be provided with a tail portion 2, the tail ends of both the negative electrode 102 and the separator 103 can be provided with a tail portion 2, or the tail ends of all three electrodes can be provided with a tail portion 2.

[0052] At the same time, such as Figure 1 As shown, the tail section 2 wraps around the main body 1, which can fix the main body 1.

[0053] Specifically, the tail section 2 can be wound around the body 1 along the winding direction and connected to the body 1 by the tail tape 3, so as to realize the connection between the tail section 2 and the body 1, and the fixation of the tail section 2 to the body 1.

[0054] Specifically, the tail portion 2 can be wound less than one revolution, one revolution, or more than one revolution around the body 1. To address the problem in related technologies where the electrodes of the wound cell 100 are prone to breakage under varying internal stress, the tail portion 2 is provided with at least one fold-back portion 201. The fold-back portion 201 is formed by folding the tail portion 2 back along the winding direction, and is adapted to be straightened along the winding direction when the volume of the body 1 increases. Specifically, the fold-back portion 201 can be formed by a partial fold of the tail portion 2 back once or repeatedly folding it back in the winding direction, such as... Figure 1 The folded portion 201 is formed by folding back and forth twice in the winding direction of a portion of the tail portion 2.

[0055] By providing a foldback portion 201 at the end portion 2, the foldback portion 201 can be straightened along the winding direction under the action of the internal stress generated during the electrochemical cycle of the wound cell 100, thereby reducing the internal stress of the wound cell 100, reducing the probability of electrode breakage, and thus making the wound cell 100 less prone to electrode breakage.

[0056] In some embodiments, the wound cell 100 further includes a finishing tape 3, and the tail end of the finishing portion 2 is connected to the outermost ring of the body 1 through the finishing tape 3.

[0057] The wound battery cell 100 of this utility model embodiment can fix the tail end of the tail portion 2 to the outermost ring of the body 1 by setting the tail adhesive paper 3, so that the body 1 and the tail portion 2 of the wound battery cell 100 can be fixed together to form a stable wound battery cell 100 structure.

[0058] In some embodiments, in the width direction of the wound cell 100, the fold-back portion 201 is misaligned with the positive electrode tab 1011 and the negative electrode tab 1021, that is, the projection of the fold-back portion 201 in the thickness direction of the wound cell 100 does not overlap with the projection of the positive electrode tab 1011 or the negative electrode tab 1021 in the thickness direction of the wound cell 100.

[0059] Furthermore, in the width direction of the wound cell 100,

[0060] At least one of the said folded portions 201 is disposed between the positive electrode tab 1011 and the negative electrode tab 1021; and / or,

[0061] At least one of the said folded portions 201 is opposite to the positive electrode tab 1011 or the negative electrode tab 1021; and / or,

[0062] At least one of the said folded portions 201 is located between the side of the positive electrode tab 1011 opposite to the negative electrode tab 1021 and the arcuate region of the body 1; and / or,

[0063] At least one of the folded portions 201 is located between the side of the negative electrode tab 1021 facing away from the positive electrode tab 1011 and the arcuate area of ​​the body 1.

[0064] It is understandable that in the wound cell 100, due to the setting of the positive and negative tabs and the protective adhesive paper near the positive and negative tabs (such as the adhesive paper covering the tabs, the adhesive paper covering the electrode sheet on the back side of the tabs, and the adhesive paper covering the electrode sheet on the opposite side of the tabs), the thickness of different areas of the battery is different. The thickness difference will cause local stress concentration and structural failure in the wound cell 100, which will lead to a deterioration in the cycle performance of the battery, and may also bring risks such as damage to the separator 103, thermal runaway, and internal short circuit.

[0065] It is understandable that the thickness varies in different areas of the battery. In other words, the main body has a thickness reduction area, and the thickness of the thickness reduction area is less than the preset thickness of the main body. The preset thickness of the main body can be understood as the designed thickness of the main body, or it can be understood as the other areas of the main body excluding the thickness reduction area.

[0066] Therefore, the aforementioned fold-back portion 201 can be provided in the thickness reduction area (such as between the positive and negative tabs) to compensate for the thickness difference, so that the thickness of each area of ​​the wound cell 100 is consistent, greatly improving the flatness of the wound cell 100.

[0067] Furthermore, in the width direction of the wound cell 100, a fold-back portion 201 is provided between the positive electrode tab 1011 and the negative electrode tab 1021.

[0068] It is understandable that the wound battery cell 100 has a positive tab 1011 and a negative tab 1021. Due to the tabs and protective adhesive paper, they are often quite thick. At the same time, a thinner area is formed between the two thicker areas. Therefore, in the width direction of the wound battery cell 100, the fold-back portion 201 is located between the positive tab 1011 and the negative tab 1021. The fold-back portion 201 can compensate for the thickness difference between the positive tab 1011 and the negative tab 1021, so that the thickness of each area of ​​the wound battery cell 100 is consistent, which greatly improves the flatness of the wound battery cell 100.

[0069] In some embodiments, the number of fold-back portions 201 is 1-6, for example, the number of fold-back portions 201 is 1, 2, 3, 4, 5 or 6.

[0070] Preferably, the number of folded portions 201 is 1 (e.g., Figure 1 (as shown) or 2 (as shown) Figure 4 (As shown).

[0071] In some embodiments, the fold-back portion 201 includes at least two or more even-numbered fold-back angles 2011.

[0072] By setting the fold angle 2011 of the fold-back portion 201 to two or more even numbers, that is, by folding the fold-back portion 201 back two or more times, the extension directions of the beginning and end of the fold-back portion 201 are the same, which makes it easier for the fold-back portion 201 to be straightened along the winding direction under the action of the internal stress generated during the electrochemical cycle of the winding cell 100.

[0073] Furthermore, the number of fold angles 2011 of the folded portion 201 is an even number between 2 and 10. For example, the number of fold angles 2011 of the folded portion 201 is 2, 4, 6, 8 or 10.

[0074] Preferably, the number of fold angles 2011 of the folded portion 201 is 2 (e.g., Figure 1-2 (as shown) or 4 (as shown) Figure 3 (As shown).

[0075] In some embodiments, the fold-back length of the fold-back portion 201 in the length direction of the tail portion 2 is 0.5-50 mm.

[0076] Preferably, the fold-back length of the fold-back portion 201 in the length direction of the tail portion 2 is 0.5-5mm.

[0077] In some embodiments, the termination portion 2 connected to the tail end of the positive electrode 101 is a positive electrode termination portion 2, which is a foil integrally formed with the current collector of the positive electrode 101; and / or,

[0078] The tail portion 2 connected to the tail end of the negative electrode 102 is the negative electrode tail portion 2, which is a foil integrally formed with the current collector of the negative electrode 102; and / or,

[0079] The tail section 2 connected to the tail end of the diaphragm 103 is the diaphragm tail section 2, and the diaphragm tail section 2 is integrally formed with the diaphragm 103.

[0080] As mentioned above, the wound battery cell 100 of this utility model embodiment may have a tail end 2 connected to the tail end of the positive electrode 101, a tail end 2 connected to the tail end of the separator 103, a tail end 2 connected to the tail end of the negative electrode 102, a tail end 2 connected to the tail ends of both the positive electrode 101 and the negative electrode 102, a tail end 2 provided at the tail ends of both the positive electrode 101 and the separator 103, a tail end 2 provided at the tail ends of both the negative electrode 102 and the separator 103, or a tail end 2 provided at the tail ends of the positive electrode 101, the negative electrode 102 and the separator 103.

[0081] For example, the tail portion 2 connected to the tail end of the positive electrode 101 is the positive electrode tail portion 2, which is a foil material integrally disposed with the current collector of the positive electrode 101.

[0082] For example, the tail portion 2 connected to the tail end of the negative electrode 102 is the negative electrode tail portion 2, which is a foil material integrally disposed with the current collector of the negative electrode 102.

[0083] For example, the tail end 2 connected to the tail end of the diaphragm 103 is the diaphragm tail end 2, and the diaphragm tail end 2 is integrally formed with the diaphragm 103.

[0084] For example, the tail end 2 connected to the tail end of the positive electrode 101 is the positive electrode tail end 2, which is a foil material integrally formed with the current collector of the positive electrode 101; the tail end 2 connected to the tail end of the negative electrode 102 is the negative electrode tail end 2, which is a foil material integrally formed with the current collector of the negative electrode 102.

[0085] For example, the tail end 2 connected to the tail end of the positive electrode 101 is the positive electrode tail end 2, which is a foil material integrally formed with the current collector of the positive electrode 101. The tail end 2 connected to the tail end of the separator 103 is the separator tail end 2, which is integrally formed with the separator 103.

[0086] For example, the tail end 2 connected to the tail end of the negative electrode 102 is the negative electrode tail end 2, which is a foil material integrally formed with the current collector of the negative electrode 102. The tail end 2 connected to the tail end of the diaphragm 103 is the diaphragm tail end 2, which is integrally formed with the diaphragm 103.

[0087] For example, the tail portion 2 connected to the tail end of the positive electrode 101 is the positive electrode tail portion 2, which is a foil material integrally formed with the current collector of the positive electrode 101; the tail portion 2 connected to the tail end of the negative electrode 102 is the negative electrode tail portion 2, which is a foil material integrally formed with the current collector of the negative electrode 102; and the tail portion 2 connected to the tail end of the separator 103 is the separator tail portion 2, which is integrally formed with the separator 103.

[0088] It is understandable that the specific settings can be configured according to actual needs.

[0089] This utility model also provides a battery.

[0090] The battery of this novel embodiment includes the wound cell 100 described in the above embodiment.

[0091] The battery of this utility model embodiment has a wound cell 100 with a fold-back portion 201 provided at the end 2. Under the action of the internal stress generated during the electrochemical cycle of the wound cell 100, the fold-back portion 201 can be straightened along the winding direction, thereby reducing the internal stress of the wound cell 100, reducing the probability of electrode breakage, and thus making the battery less prone to electrode breakage.

[0092] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. A wound battery cell, characterized in that, include: The body (1) includes a positive electrode (101), a negative electrode (102) and a separator (103). The positive electrode (101), the separator (103) and the negative electrode (102) are stacked and wound along the winding direction to form the body (1). The positive electrode plate (101) is provided with a positive electrode tab (1011), and the negative electrode plate (102) is provided with a negative electrode tab (1021). Tail section (2): The tail end of at least one of the positive electrode (101), the separator (103) and the negative electrode (102) is connected to the tail section (2) and wraps the body (1). The tail portion (2) is provided with at least one folded portion (201), which is formed by folding the tail portion (2) back along the winding direction. The folded portion (201) is adapted to be straightened along the winding direction when the volume of the body (1) increases.

2. The wound battery cell according to claim 1, characterized in that, In the width direction of the wound cell (100), at least one of the folded-back portions (201) is misaligned with either the positive electrode tab (1011) or the negative electrode tab (1021); and / or, In the thickness direction of the wound cell (100), at least one of the folded portions (201) is positioned opposite to the positive tab (1011) or the negative tab (1021).

3. The wound battery cell according to claim 2, characterized in that, In the width direction of the wound cell (100), At least one of the folded portions (201) is disposed between the positive electrode tab (1011) and the negative electrode tab (1021); and / or, At least one of the said folded portions (201) is opposite to the positive electrode tab (1011) or the negative electrode tab (1021); and / or, At least one of the folded portions (201) is located between the side of the positive electrode tab (1011) facing away from the negative electrode tab (1021) and the arcuate region of the body (1); and / or, At least one of the folded portions (201) is located between the side of the negative electrode tab (1021) facing away from the positive electrode tab (1011) and the arcuate area of ​​the body (1).

4. The wound battery cell according to claim 3, characterized in that, The body has a thickness reduction area, the thickness of which is less than the preset thickness of the body, and the folded portion is located in the thickness reduction area.

5. The wound battery cell according to claim 2, characterized in that, The wound cell (100) also includes a finishing tape (3), and the end of the finishing part (2) is connected to the outermost ring of the body (1) through the finishing tape (3).

6. The wound battery cell according to claim 1, characterized in that, The number of the folded sections (201) is 1-6.

7. The wound battery cell according to claim 1, characterized in that, The folded portion (201) includes at least two or more even-numbered folded angles (2011).

8. The wound battery cell according to claim 1, characterized in that, The fold-back length a of the fold-back portion (201) in the length direction of the tail portion (2) is 0.5-50mm.

9. The wound battery cell according to claim 1, characterized in that, The tail portion (2) connected to the tail end of the positive electrode (101) is a positive electrode tail portion (2), which is a foil integrally formed with the current collector of the positive electrode (101); and / or, The tail portion (2) connected to the tail end of the negative electrode sheet (102) is a negative electrode tail portion (2), and the negative electrode tail portion (2) is a foil integrally formed with the current collector of the negative electrode sheet (102); and / or, The tail portion (2) connected to the tail end of the diaphragm (103) is the tail portion (2) of the diaphragm (103), and the tail portion (2) of the diaphragm (103) is integrally formed with the diaphragm (103).

10. A battery, characterized in that, Includes the wound cell (100) as described in any one of claims 1-9.

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