Battery and battery cell thereof

Abstract

The utility model provides a battery and a battery cell thereof. The battery cell comprises a body and a battery cell, a middle space is formed in the body; the body is provided with a plurality of enclosing parts; the enclosing parts surround the middle space so that at least one part of the boundary of the middle space can be defined by the enclosing parts. In the embodiment of the utility model, the forming mode of the battery cell is changed, and at least one part of the enclosing part is formed at the periphery of the middle space in a surrounding manner, so that a gap can be formed between the enclosing parts, and the condition that the inner layer and the outer layer of the laminated pole piece are in close contact in a conventional winding forming manner is avoided; and the ion concentration of the region, close to the middle space, of the enclosure part is reduced in a manner of obtaining the gaps among the enclosure parts, so that the technical problems of poor heat dissipation and non-uniform current distribution in the battery are solved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to batteries and their cells. Background Technology

[0002] In related technologies, electrode stacking methods mainly include two types: winding and stacking. Among them, the winding method is more common in cylindrical batteries and is occasionally used in prismatic batteries. The winding method involves stacking the positive electrode, separator, and negative electrode and then winding them onto the negative electrode post to form a cell. Then, it is encapsulated with a steel or aluminum shell, injected with electrolyte, and then sealed.

[0003] Batteries formed by winding have a relatively high ion concentration (such as lithium ions) in the inner ring where the cell curvature changes significantly. This can easily lead to uneven current distribution and large voltage polarization during cell discharge, resulting in a low discharge voltage plateau. At the same time, because the electrodes are wound from the inside out, the inner part of the electrodes is not easy to dissipate heat, which can lead to problems such as poor radial thermal conductivity in cylindrical batteries. Utility Model Content

[0004] The present invention provides a battery and its cell that can improve the technical problems of poor heat dissipation and uneven current distribution in battery cells.

[0005] In a first aspect, embodiments of the present invention provide a battery cell, comprising:

[0006] The main body has a central space;

[0007] The main body has multiple enclosing portions; the multiple enclosing portions surround the central space so that the enclosing portions define at least a portion of the boundary of the central space.

[0008] In one embodiment, the enclosure includes:

[0009] The first bend is formed at one end of the enclosed section near the central space;

[0010] The first bending segment of the multiple enclosing parts is set at intervals.

[0011] In one embodiment, the enclosure further includes:

[0012] The second bend is formed at the end of the enclosure that is far from the central space;

[0013] The second bending sections of the multiple enclosing parts are spaced apart.

[0014] In one embodiment, the enclosure further includes:

[0015] The first connecting segment connects the first end of the first bent segment and the first end of the second bent segment;

[0016] The second connecting segment is connected to the second end of the second connecting segment;

[0017] Wherein, at least part of the second connecting segment of the enclosure is connected to the second end of the first bending segment of the adjacent enclosure, so as to form an outer partition space between the first connecting segment, the first bending segment and the second connecting segment of the two adjacent enclosures.

[0018] In one embodiment, the first connecting segment and the second connecting segment are spaced apart to form an inner partition space between the first connecting segment, the second bending segment, and the second connecting segment;

[0019] The outer and inner partition spaces are separated by an enclosure.

[0020] In one embodiment, the thickness of the enclosure portion at the first bend is less than the thickness of the first connecting segment; and / or the thickness of the enclosure portion at the second bend is less than the thickness of the first connecting segment.

[0021] In one embodiment, the body includes a positive electrode, a separator layer, and a negative electrode stacked together;

[0022] The separator layer is located between the positive electrode and the negative electrode to separate them; the stacked positive electrode, separator layer and negative electrode extend to the periphery of the central space to form an enclosure.

[0023] In one embodiment, multiple enclosure portions are distributed in a circular pattern around a central axis on the periphery of the central space;

[0024] The ratio of the minimum distance from the enclosure to the central axis to the maximum distance from the enclosure to the central axis ranges from 1 / 10 to 1 / 3; and / or,

[0025] The ratio of the sum of the maximum distances from the two enclosures to the central axis to the length of the membrane layer in the straight line direction of the central axis ranges from 0.3 to 3.

[0026] In one embodiment, on the projection plane with the central axis as the normal, a projection circle is defined with the projection point of the central axis as the center and the distance from the point where the projection of each enclosing part is farthest from the central axis to the central axis as the radius; the projection of the boundary of the outer partition space formed by the enclosing part on the projection plane is defined as the projection boundary line; the ratio of the area of ​​the region enclosed by the projection circle and the projection boundary line to the area of ​​the projection circle ranges from 0.05 to 0.3.

[0027] Secondly, embodiments of this utility model provide a battery comprising any of the aforementioned cells.

[0028] The beneficial effects of the embodiments of this utility model are as follows:

[0029] In the embodiments of this utility model, by changing the forming method of the battery cell, at least a portion of the enclosure is formed around the periphery of the central space in a surrounding manner, which can form gaps between the enclosures, instead of having the inner and outer layers of the stacked electrode sheets in close contact as in the conventional winding forming method. This allows for enhanced heat transfer through gaps to improve heat dissipation, and by obtaining gaps between multiple enclosures, the ion concentration in the region near the central space is reduced, thereby improving the technical problems of poor heat dissipation and uneven current distribution in the battery. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments 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.

[0031] Figure 1 This is a three-dimensional schematic diagram of the battery cell provided in an embodiment of this utility model;

[0032] Figure 2 This is a schematic diagram of the battery cell projected onto a projection surface according to an embodiment of this utility model;

[0033] Figure 3 This is a schematic diagram of the structure of the enclosure portion in the battery cell provided in an embodiment of the present invention;

[0034] Figure 4 yes Figure 2 A magnified view of part A in the middle;

[0035] Figure 5 yes Figure 2 A magnified view of part B in the middle section;

[0036] Figure 6 This is a schematic diagram showing the relationship between the projected circle and the projected boundary line in the battery cell provided by an embodiment of this utility model;

[0037] Figure 7 This is an exploded view of the battery cell provided in an embodiment of this utility model.

[0038] Explanation of reference numerals in the attached figures:

[0039] 10. Battery;

[0040] 100. Battery cells;

[0041] 110. Main body; 110a. Central space; 110b. Inner partition space; 110c. Outer partition space;

[0042] 111. Enclosing section; 111a. First bending section; 111b. Second bending section; 111c. First connecting section; 111d. Second connecting section;

[0043] 112. Positive electrode plate;

[0044] 113. Diaphragm layer;

[0045] 114. Negative electrode plate;

[0046] 115. The first and final section;

[0047] 116. The second and final section;

[0048] X1, First direction; A1, Central axis; S, Projection plane; A2, Projection circle; A3, Projection boundary line. Detailed Implementation

[0049] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present utility model and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0050] Reference Figures 1 to 7 As shown, an embodiment of this utility model provides a battery cell 100, including a body 110. Specifically, when the body 110 is integrated into a battery, it functions as a conductor within the battery. The body 110 forms a central space 110a. To improve the poor heat dissipation and uneven current distribution of the battery cell 100, the body 110 is provided with multiple enclosure portions 111, which surround the central space 110a, thus defining at least a portion of the boundary of the central space 110a. In conventional wound battery cell 100 construction, electrodes are stacked layer by layer from the inner to the outer layer around the periphery of a region, with adjacent layers being in close contact. In this utility model, the battery cell 100 forms multiple enclosure portions 111, which are arranged around a region and can be distributed around the periphery of that region.

[0051] By adopting the above solution, by changing the forming method of the cell 100, at least a portion of the enclosure portion 111 is formed around the periphery of the central space 110a in a surrounding manner. Gaps can be formed between each enclosure portion 111, instead of having the inner and outer layers of the stacked electrode sheets in close contact as in the conventional winding forming method. This allows for enhanced heat transfer through gaps to improve heat dissipation. Furthermore, by obtaining gaps between multiple enclosure portions 111, the ion concentration in the region near the central space 110a is reduced, thereby improving the technical problems of poor heat dissipation and uneven current distribution in the battery.

[0052] It should be noted that the battery cell 100 formed in the surrounding manner in this utility model emphasizes the presence of a gap between adjacent enclosing portions 111. Therefore, this utility model does not specifically limit how it is formed in the surrounding manner. To clearly illustrate the inventive concept of this utility model, some specific embodiments of the surrounding formation will be described below by way of example.

[0053] In one embodiment, reference is made to Figure 2 , Figure 3 and Figure 4 As shown, the enclosing portion 111 includes a first bent segment 111a. The first bent segment 111a is formed at one end of the enclosing portion 111 near the central space 110a. During its extension, the enclosing portion 111 changes direction at the first bent segment 111a, for example, from gradually approaching the central space 110a to gradually moving away from the central space 110a; that is, the enclosing portion 111 forms a turning shape at the first bent segment 111a. This turning shape can be arc-shaped, meaning the extension direction of the enclosing portion 111 at the first bent segment 111a changes continuously. The turning shape can also be angled, meaning the extension direction of the enclosing portion 111 at the first bent segment 111a changes abruptly. In this embodiment, the first bent segments 111a of multiple enclosing portions 111 are spaced apart, thereby forming gaps between adjacent first bent segments 111a. Considering that the battery cell 100 experiences thermal expansion and contraction during use, these gaps provide space for the expansion of the battery cell 100. Furthermore, the electrolyte can flow into the gap to ensure that the electrolyte is in full contact with the battery cell 100.

[0054] In one embodiment, reference is made to Figure 2 , Figure 3 and Figure 5As shown, the enclosing portion 111 further includes a second bent segment 111b. The second bent segment 111b is formed at the end of the enclosing portion 111 away from the central space 110a. During its extension, the enclosing portion 111 changes direction at the second bent segment 111b, for example, from gradually moving away from the central space 110a to gradually moving closer to the central space 110a; that is, the enclosing portion 111 also forms a turning shape at the second bent segment 111b. This turning shape can be arc-shaped, meaning the extension direction of the enclosing portion 111 changes continuously at the second bent segment 111b. The turning shape can also be angled, meaning the extension direction of the enclosing portion 111 changes abruptly at the second bent segment 111b. The cooperation of the first bent segment 111a and the second bent segment 111b also enables adjacent enclosing portions 111 to connect with each other through changes in their extension directions, thereby enclosing each enclosing portion 111 around the periphery of the central space 110a.

[0055] The second bending segments 111b of the plurality of enclosure portions 111 are spaced apart, thereby forming gaps between adjacent first bending segments 111a. These gaps prevent close contact between adjacent enclosure portions 111, allowing the battery cell 100 to exchange heat with the outside environment and improving its heat dissipation capacity. Furthermore, electrolyte can flow into the gaps to ensure sufficient contact between the electrolyte and the battery cell 100.

[0056] In one embodiment, reference is made to Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the enclosure 111 further includes a first connecting segment 111c and a second connecting segment 111d. The first connecting segment 111c is connected between the first end of the first bent segment 111a and the first end of the second bent segment 111b. The second connecting segment 111d is connected to the second end of the second connecting segment 111d. At least a portion of the second end of the second connecting segment 111d of the enclosure 111 is connected to the second end of the first bent segment 111a of an adjacent enclosure 111, thereby forming an outer partition space 110c between the first connecting segments 111c, the first bent segment 111a, and the second connecting segment 111d of two adjacent enclosures 111. Specifically, the first connecting segment 111c and the second connecting segment 111d can extend along various patterns such as arcs and wavy lines, which can be used to increase the contact area between the battery cell 100 and the electrolyte. Alternatively, the first connecting segment 111c and the second connecting segment 111d can extend in a straight line, which is convenient for process implementation during production. The setting of the outer partition space 110c can increase the contact area between the electrolyte and the cell 100. When the cell 100 is working, it can dissipate heat into the outer partition space 110c through the surface forming the boundary of the outer partition space 110c, thereby enhancing the heat dissipation capacity of the cell.

[0057] In one embodiment, the first connecting segment 111c and the second connecting segment 111d are spaced apart to form an inner partition space 110b between the first connecting segment 111c, the second bending segment 111b, and the second connecting segment 111d. The inner partition space 110b ensures that the surface of the cell 100 is in full contact with the electrolyte, while preventing adjacent enclosure segments from being completely tightly fitted together. When the cell 100 is working, heat can be dissipated into the inner partition space 110b through the surface forming the boundary of the inner partition space 110b. Subsequently, heat is transferred to the battery casing in which the cell 100 is integrated through the inner partition space 110b, thereby enhancing the heat dissipation effect of the cell 100.

[0058] The outer partition space 110c and the inner partition space 110b are separated by the enclosure portion 111. That is, the surfaces of the cell 100 that form the boundaries of the outer partition space 110c and the inner partition space 110b can be different. This arrangement allows multiple surfaces of the cell 100 to be used for external heat dissipation. In particular, the enclosure portion 111 can have good heat dissipation in all directions from near the central space 110a to gradually away from the central space 110a.

[0059] The body 110 can be a structure formed by connecting various enclosure portions 111 together through a second connecting segment 111d and a first bent segment 111a of another enclosure portion 111. Each enclosure portion 111 can be integrally formed, that is, each enclosure portion 111 is an inseparable part of the overall body 110. In one embodiment, referring to... Figure 2 As shown, when each enclosure 111 surrounds the periphery of the central space 110a, the two enclosures 111 located at both ends of the body 110 do not need to be connected to each other. As an example, the first connecting segment 111c of one enclosure 111 located at one end of the body 110 is integrally formed with a first tail segment 115, while the other enclosure 111 located at the other end of the body 110 is integrally formed with a second tail segment 116. The first tail segment 115 and the second tail segment 116 do not form a fixed connection, so that the two ends of the body 110 are not connected as one piece.

[0060] In one embodiment, the thickness of the enclosure portion 111 at the first bending section 111a is less than the thickness of the first connecting section 111c. And / or the thickness of the enclosure portion 111 at the second bending section 111b is less than the thickness of the first connecting section 111c. That is, during the process of forming the raw material of the battery cell 100 surrounding the periphery of the central space 110a, the thickness of the bent portion of the battery cell 100 can be reduced. Considering that metal materials are often used as electrodes in the raw material of the battery cell 100, this arrangement facilitates bending of the raw material and avoids breakage of the raw material at the bending point.

[0061] An exemplary description of the specific structure by which the battery cell 100 serves as an electrode to achieve conductivity is provided in one embodiment, referring to... Figure 7 As shown, the body 110 includes a positive electrode 112, a separator layer 113, and a negative electrode 114 stacked together. The separator layer 113 is located between the positive electrode 112 and the negative electrode 114 to separate them. The stacked positive electrode 112, separator layer 113, and negative electrode 114 extend outwards from the periphery of the central space 110a to form an enclosure 111. The positive electrode 112 and negative electrode 114 can be made of conductive metal material, and the separator layer 113 serves to form insulation between them. When the cell 100 is integrated into a battery, the positive electrode 112 and negative electrode 114 are connected to different terminals of the battery, or one of the positive electrode 112 and negative electrode 114 can be connected to a battery terminal, while the other is connected to the battery casing. Therefore, when the battery is in use, the positive electrode 112 and the negative electrode 114 serve as conductors to conduct the electrical energy generated during the chemical reaction of the electrolyte to the circuit connected to the battery. Depending on the specific type of battery, such as lithium batteries or nickel-cadmium batteries, the materials used to make the positive electrode 112 and the negative electrode 114 can vary. Those skilled in the art can choose flexibly, and this is not the focus of this invention; therefore, it will not be elaborated upon here.

[0062] In one embodiment, the positive electrode 112 protrudes from one end of the separator layer 113 along the first direction X1. The negative electrode 114 protrudes from the other end of the separator layer 113 along the first direction X1, so that the ends of the positive electrode 112 and the negative electrode 114 can be flattened subsequently.

[0063] As a first specific example, this invention defines a plurality of enclosing portions 111 circumferentially distributed around a central axis A1 around the periphery of the central space 110a. This results in the formed cell 100 being cylindrical, and when the cell 100 is integrated into a cylindrical battery, this form of cell 100 can fully utilize the internal space of the cylindrical battery casing. More specifically, the central axis A1 is, for example, arranged parallel to the aforementioned first direction X1, and the central space 110a extends through the body 110 along the first direction X1, so that the cell 100 utilizes the central space 110a to transfer heat to the battery casing.

[0064] It should be noted that the battery manufacturing process requires flattening the positive electrode 112 and negative electrode 114 on the cell 100. This flattening is often achieved by using a rotating flat plate to press the portion of the positive electrode 112 or negative electrode 114 that extends beyond the separator, forming the tabs. Compared to the winding method, the tabs are more easily flattened by the wrap-around cell 100 forming method, which can reduce problems such as cracking and shedding of the positive electrode 112 or negative electrode 114 that occur during flattening.

[0065] In the first specific example above, refer to Figure 2 and Figure 4 As shown, the ratio of the minimum distance d1 from the enclosure portion 111 to the central axis A1 to the maximum distance d2 from the enclosure portion 111 to the central axis A1 can be further limited to a range of 1 / 10 to 1 / 3. This is because the closer the enclosure portion 111 is to the central axis A1 (i.e., the location of the first bend), the fewer enclosure portions 111 can be placed around the central space 110a, considering the thickness of the enclosure portion 111. Conversely, the farther the enclosure portion 111 is from the central axis A1, or the closer the enclosure portion 111 is to the central axis A1 (i.e., the location of the second bend), the lower the space utilization rate of the battery's internal space for placing the battery cell 100, thus limiting the battery capacity. Furthermore, the farther the enclosure portion 111 is from the central axis A1, the larger the size of the battery cell 100 needs to be. The aforementioned size constraints help ensure that the battery has sufficient capacity while allowing for a reasonable battery volume.

[0066] In the first specific example described above, the ratio of the sum of the maximum distances from the two enclosing portions 111 to the central axis A1 to the length of the separator layer 113 in the straight line direction of the central axis A1 (hereinafter referred to as the height h of the separator) can be further limited to a range of 0.3 to 3. Since each enclosing portion 111 is circumferentially distributed around the central axis A1, the sum of the maximum distances from the two enclosing portions 111 to the central axis A1 can be considered as the diameter of the circle formed by the distance from the second bending segment 111b of the enclosing portion 111 to the central axis A1 at the farthest point from the axis of rotation. By limiting the ratio of the diameter of this circle to the height h of the separator, the ratio of the diameter to the height of the cylindrical cell 100 is limited, avoiding the cell 100 from being too low and flat, or the cell 100 from being too small and elongated, thus facilitating processing and production while ensuring that the battery has sufficient battery capacity.

[0067] When defined on the projection plane S with the central axis A1 as the normal, the circle formed by taking the projection point of the central axis A1 as the center and the distance from the point of greatest distance from the central axis A1 to the central axis as the radius is defined as the projection circle A2. Furthermore, the projection of the boundary of the outer partition space 110c formed by the enclosing parts onto the projection plane S is defined as the projection boundary line A3. In the first specific example above, referring to... Figure 6As shown, the ratio of the area enclosed by the projection circle A2 and the projection boundary line A3 to the area of ​​the projection circle A2 can be further limited to a range of 0.05 to 0.3. This limitation can improve the heat dissipation of the cell 100 by utilizing the gap between the enclosing portions 111, while avoiding excessive dispersion of the conductive parts of the cell 100, so as to avoid excessive dispersion of the electric field distribution inside the battery.

[0068] As a second specific example, depending on the shape of the formed battery, multiple enclosure portions 111 can be arranged around the periphery of the central space 110a, making the cross-sectional shape of the formed cell 100 generally quadrilateral (of course, rounded corners can be formed at the edge connection points of the quadrilateral), so that the cell 100 can make full use of the internal space of the square battery casing when integrated into the square battery. These two specific examples are merely exemplary illustrations of the surrounding form of the enclosure portions 111. Those skilled in the art can flexibly adjust the surrounding form of the enclosure portions 111 according to the shape of the battery. This second specific example is not shown in the accompanying drawings.

[0069] Secondly, embodiments of this utility model provide a battery including the aforementioned battery cell. This battery possesses the beneficial effects of the aforementioned battery cell, which will not be elaborated upon here. As a specific example, the battery may be, for example, a cylindrical battery.

[0070] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. An electric cell, characterized by, Comprising: a body formed with a middle space; wherein the body is provided with a plurality of enclosing portions; the plurality of enclosing portions surround the middle space, so that the enclosing portions define at least part of the boundary of the middle space.

2. The battery cell according to claim 1, wherein the enclosing portion comprises: a first bent section formed at one end of the enclosing portion close to the middle space; wherein the first bent sections of the plurality of enclosing portions are arranged at intervals.

3. The battery cell according to claim 2, wherein the enclosing portion further comprises: a second bent section formed at one end of the enclosing portion away from the middle space; wherein the second bent sections of the plurality of enclosing portions are arranged at intervals.

4. The battery cell according to claim 3, wherein the enclosing portion further comprises: a first connecting section connected between a first end of the first bent section and a first end of the second bent section; a second connecting section connected to a second end of the second connecting section; wherein the second end of the second connecting section of at least part of the enclosing portion is connected to the second end of the first bent section of another adjacent enclosing portion, so as to form an outer partition space between the first connecting section, the first bent section and the second connecting section of the two adjacent enclosing portions.

5. The battery cell according to claim 4, wherein the first connecting section and the second connecting section are arranged at intervals to form an inner partition space between the first connecting section, the second bent section and the second connecting section; wherein the outer partition space and the inner partition space are separated by the enclosing portion.

6. The battery cell according to claim 4, wherein the thickness of the enclosing portion at the first bent section is less than the thickness of the first connecting section; and / or the thickness of the enclosing portion at the second bent section is less than the thickness of the first connecting section.

7. The battery cell according to any one of claims 4 to 6, wherein the body comprises a positive electrode sheet, a separator layer and a negative electrode sheet arranged in layers; wherein the separator layer is located between the positive electrode sheet and the negative electrode sheet to separate the positive electrode sheet and the negative electrode sheet; the positive electrode sheet, the separator layer and the negative electrode sheet arranged in layers extend peripherally in the middle space to form the enclosing portion.

8. The battery cell according to claim 7, wherein the plurality of enclosing portions are circumferentially distributed peripherally in the middle space around a central axis; the ratio of the minimum distance of the enclosing portion to the central axis to the maximum distance of the enclosing portion to the central axis is in the range of 1 / 10 to 1 / 3; and / or the ratio of the sum of the maximum distances of two enclosing portions to the central axis to the length of the separator layer in the direction of the straight line where the central axis is located is in the range of 0.3 to 3.

9. The battery cell according to claim 8, wherein On a projection plane which is normal to the center axis, a circle with a projection point of the center axis as a center and a distance from a point of each of the enclosing portions farthest from the center axis to the center axis as a radius is defined as a projection circle; and a projection of a boundary of the enclosing portions forming the outer insulating layer space on the projection plane is defined as a projection boundary line; A ratio of an area of a region enclosed by the projection circle and the projection boundary line to an area of the projection circle is in a range of 0.05 to 0.

3.

10. A battery, characterized by An electric device comprising the electric cell according to any one of claims 1 to 9.

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