Battery and battery pack comprising same

Abstract

The present application relates to the technical field of batteries, and specifically provides a battery and a battery pack comprising same. The battery comprises a housing and a battery cell; the housing is made of steel and has two straight edges and two arc edges, jointly defining a cavity; the cross-sectional area of the housing is b, the cross-sectional area of the battery cell is a, the cross section of the housing has a maximum length m and a maximum width n, c=m×n, and 0.2≤a*c / b2≤20. In the present application, the battery housing is a racetrack-shaped steel housing, which not only retains the advantages of high strength and corrosion resistance of steel, but also eliminates the right-angle corner characteristics of rectangular housings, thereby overcoming the poor ductility of steel, and avoiding edge thinning and cracking of a tube blank during the forming process; in addition, the housing provided by the present application is dimensionally matched with the battery cell disposed in the housing, thus preventing shaking of the battery cell in the housing and tab breakage caused thereby, and preventing compression of the battery cell. The design of the present application is simple and ingenious, improving the forming yield of the housing and reducing manufacturing costs.

Description

Batteries and battery packs including the same

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411699847.3, filed on November 26, 2024, entitled "Battery and Battery Pack Including the Same", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the technical field of batteries, and specifically proposes a battery and a battery pack including the same. Background Technology

[0004] In related technologies, square batteries usually refer to batteries with square steel casings. They have high energy density and long cycle life, and are therefore widely used in many fields.

[0005] However, in the process of manufacturing the casing of square batteries, the curved edge of the tube blank needs to be formed into a right angle. Due to the poor ductility of steel, the edge thickness will become thinner in this process, which will make it easy to crack and affect the molding yield of the battery casing. Summary of the Invention

[0006] The purpose of this application is to solve at least some of the technical problems mentioned above, and this purpose is achieved through the following technical solutions:

[0007] In a first aspect, this application proposes a battery comprising a casing and a battery cell disposed inside the casing; the casing is made of steel and has two oppositely arranged straight edges and two oppositely arranged arc edges, the two arc edges connecting the two straight edges and surrounding to form a cavity for accommodating the battery cell; the casing has an opening oriented in the Z direction, and in the direction perpendicular to Z, the cross-sectional area of ​​the casing is b, the cross-sectional area of ​​the battery cell is a, the maximum length of the casing cross-section is m, the maximum width is n, c = m × n, then 0.2 ≤ a * c / b 2 ≤20.

[0008] In some embodiments, 0.1 ≤ a / b ≤ 0.9.

[0009] In some embodiments, the cross-sectional area b of the housing is in the range of 3848 mm². 2 ≤b≤37000mm 2 .

[0010] In some embodiments, the cross-sectional area 'a' of the battery cell is in the range of 3675 mm². 2 ≤a≤14651mm 2 .

[0011] In some embodiments, the radian of the arc edge of the housing (100) is r, and the range of r*(a / b) is 0.1≤r*(a / b)≤2.9, in rad.

[0012] In some embodiments, the length of the straight side of the shell is L, and the range of L / m is 0.4≤L / m≤0.95.

[0013] In some embodiments, the thickness of the curved edge is less than the thickness of the straight edge.

[0014] In some embodiments, 0.12 ≤ a / b ≤ 0.85.

[0015] In some embodiments, the housing includes at least one battery cell, the battery cell including a straight section and an arcuate section, the arcuate section having a radius ratio of 0.9 to 1.1 to the arcuate edge of the housing.

[0016] In some embodiments, the housing contains only one battery cell.

[0017] In some embodiments, 0.4 ≤ L / m ≤ 0.92.

[0018] In some embodiments, the battery cell includes a separator with a porosity ≥38% and 0.15≤a / b≤0.85.

[0019] In some embodiments, the opening is provided with a first cover plate and a second cover plate, and at least one of the first cover plate and the second cover plate is provided with a liquid injection hole. The liquid injection hole is located at a distance of h1 from one end of the cover plate and at a distance of h2 from the other end in the direction extending along the straight edge of the shell, and 0.05≤h1 / h2≤20.

[0020] In some embodiments, the minimum thickness at the junction of the straight edge and the arc edge of the shell is e, then 0.08mm≤e≤0.8mm.

[0021] In some embodiments, 100mm≤m≤500mm, 15mm≤n≤80mm.

[0022] Secondly, this application proposes a battery pack comprising a plurality of batteries as described in the first aspect, wherein adjacent batteries are disposed in close contact with each other along straight edges.

[0023] In some embodiments, the range of the battery casing straight edge length L / maximum casing length m is 0.4 ≤ L / m ≤ 0.9.

[0024] In some embodiments, the gap between adjacent battery casing arc edges is d, where 0.1mm≤d≤5mm.

[0025] In some embodiments, the battery pack further includes a liquid cooling plate, which is attached to the straight edge of the battery housing, and the range of the length L of the straight edge of the battery housing / the maximum length m of the housing is 0.42 ≤ L / m ≤ 0.95.

[0026] The technical solution proposed in this application has at least the following technical effects:

[0027] In this application, the battery casing is a racetrack-shaped steel casing, which retains the advantages of high strength and corrosion resistance of steel while eliminating the right-angled characteristics of a square casing. This overcomes the disadvantage of poor ductility of steel and avoids the thinning of the edge thickness during the forming process of the tube blank, which can easily lead to cracking. In addition, the casing proposed in this application matches the size of the internal battery cell, which can prevent the battery cell from shaking inside the casing and causing the tabs to break, while also preventing the battery cell from being squeezed. This application features a simple and ingenious design, improving the casing forming yield and reducing manufacturing costs. Attached Figure Description

[0028] To better integrate the content illustrated in the accompanying drawings with the description of the specific embodiments, a brief introduction to the drawings is provided below. It is understood that the accompanying drawings mentioned below are merely schematic illustrations of some embodiments of the relevant technical solutions and the technical solutions of this application. Without creative effort, those skilled in the art can create drawings illustrating other embodiments.

[0029] Specifically, the annotations for the accompanying drawings are as follows:

[0030] Figure 1 is an isometric view of the housing described in some embodiments of this application;

[0031] Figure 2 is a top view of the housing described in some embodiments of this application.

[0032] Specifically, the annotations of the reference numerals in the accompanying drawings are as follows: 100, housing; 110, arc edge; 120, straight edge. Detailed Implementation

[0033] To make the embodiments of this application clearer, they will be described below in conjunction with the accompanying drawings. It is to be understood that the content mentioned below is only a partial embodiment of this application, while the complete list of all embodiments is provided. Therefore, other embodiments obtained based on the following embodiments without any inventive effort all fall within the protection scope of this application.

[0034] It should be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to impose strict limitations on the technical solutions unless the context clearly indicates otherwise. For example, the use of "a," "an," and "the" to modify a feature does not preclude the possibility that the feature may be plural in other embodiments.

[0035] It should be understood that the terms "comprising," "including," and "having" are open-ended, indicating the presence of the stated features but not excluding the possibility of other features in the embodiment. Similarly, the use of terms such as "first," "second," etc., to describe multiple features only indicates the distinction between one feature and another, and such terms do not imply order or sequence unless explicitly stated in the context.

[0036] It should be understood that, unless the context clearly indicates otherwise, the terms "setup," "connection," and "installation" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integrated connection; they can refer to a direct connection or an indirect connection via a medium. Those skilled in the art will understand the specific meaning of these terms in this document based on the specific circumstances.

[0037] In addition, for ease of description, the text will use terms of spatial relative relationship to describe the position of one feature relative to another feature, such as "inner", "outer", "end", "side", "upper", "middle", "lower", "high", "low", "axial", "circumferential", "radial", "horizontal", "vertical", "first direction", "second direction", etc. It can be understood that the spatial relative relationship between two features should include other specific situations besides those shown in the accompanying drawings of the specification.

[0038] The embodiments of this application will now be described with reference to the accompanying drawings.

[0039] In a first aspect, this application proposes a battery comprising a casing and a battery cell disposed inside the casing; the casing is made of steel and has two oppositely arranged straight edges 120 and two oppositely arranged arc edges, the two arc edges connecting the two straight edges 120 and surrounding to form a cavity for accommodating the battery cell; the casing has an opening oriented in the Z direction, and in the direction perpendicular to Z, the cross-sectional area of ​​the casing is b, the cross-sectional area of ​​the battery cell is a, the maximum length of the casing cross-section is m, the maximum width is n, c = m × n, then 0.2 ≤ a * c / b 2 ≤20.

[0040] Referring to Figures 1 and 2, the orientation of the shell opening is in the Z direction, the shell length direction is in the X direction, and the shell width direction is in the Y direction.

[0041] In this application, the battery casing 100 is a racetrack-shaped steel casing, which retains the advantages of high strength and corrosion resistance of steel while eliminating the right-angled characteristics of a square casing, overcoming the disadvantage of poor ductility of steel, and avoiding the thinning of the edge thickness during the forming process of the tube blank, which can easily lead to cracking. In addition, the casing 100 proposed in this application matches the size of the battery cell inside, which can prevent the battery cell from shaking inside the casing 100 and causing the tab to break, while also preventing the battery cell from being squeezed. The design of this application is concise and ingenious, improving the molding yield of the casing 100 and reducing manufacturing costs.

[0042] It should be noted that in related technologies, when forming a square shell, due to the poor ductility of steel, material tends to accumulate at the corners, which makes the edge thickness near the corners thinner and causes cracking. In this application, the runway-shaped shell 100 includes an integrally connected arc edge 110 and a straight edge 120120, eliminating right-angle features and thus overcoming the above-mentioned disadvantages.

[0043] In summary, during the forming process of the square steel shell, the curved edges of the tube blank need to be formed into right angles. Due to the poor ductility of steel, the edges become thinner during the process of turning from round to square, making the shell edges prone to cracking. Making the shell into a racetrack shape reduces the stress on the curved edges and makes the shell easier to form. At the same time, the shell and cell sizes are more matched, which improves the space utilization of the shell. Finally, when the shells are assembled, the sides of adjacent batteries are curved and form gaps. This helps the heat generated by the battery to dissipate through the gaps, overcoming the disadvantage of poor thermal conductivity of steel shells and preventing thermal runaway caused by excessive battery heat.

[0044] Furthermore, if a*c / b 2 If the value is less than the lower limit, it indicates that the space utilization within the casing is too low, the matching degree between the cell and the casing is not high, and the cell's movement within the casing will pull on the connection between the tab and the terminal, causing the tab to break; if a*c / b 2 If the value is greater than the upper limit, it indicates that the space utilization rate after grouping is too low. Low space utilization means fewer batteries can be arranged in the battery pack, affecting the overall pack density. Therefore, a*c / b 2 The value of should be moderate; for example, it can be a range of 0.2, 0.5, 1, 5, 10, 20, or any two of them.

[0045] Specifically, the battery cell can be a wound battery cell, where the positive electrode, negative electrode, and positive electrode are separated by a separator and continuously wound to form the battery cell, which becomes the smallest charging and discharging unit; or it can be a stacked battery cell, where the positive electrode, negative electrode, and positive electrode are separated by a separator and stacked to form the battery cell, which becomes the smallest charging and discharging unit.

[0046] Understandably, this application does not impose strict restrictions on the material of the steel shell, and it can be carbon steel, alloy steel, and other iron-based stainless steel, etc.

[0047] In some embodiments, 0.1 ≤ a / b ≤ 0.9.

[0048] This parameter characterizes the space utilization rate of the battery casing. The volume of the casing should match the size of the battery cell. If the casing is too large, the battery cell will move around inside the casing, pulling on the connection between the tabs and terminals, causing the tabs to break. If the casing is too small, it will compress the battery cell. If the battery cell is multi-cell, the opening area of ​​the cell is the sum of the opening areas of all the cells. Therefore, the value of a / b should be moderate, for example, it can be a range of 0.1, 0.2, 0.5, 0.6, 0.9, or any combination of two of these values.

[0049] In some embodiments, the cross-sectional area b of the housing is in the range of 3848 mm². 2 ≤b≤37000mm 2 In some embodiments, the cross-sectional area 'a' of the battery cell ranges from 3675 mm². 2 ≤a≤14651mm 2 .

[0050] The values ​​of a and b should also be appropriate. For example, a can be a range of 3675, 4000, 5000, 10000, 14651, or any combination of two of these values, in mm. 2 b can be a range of 3848, 4000, 5000, 10000, 20000, 30000, 37000, or any combination thereof, in mm. 2 .

[0051] In some embodiments, the radian of the arc edge of the housing (100) is r, and the range of r*(a / b) is 0.1≤r*(a / b)≤2.9, in rad.

[0052] When a / b is large, it means that the battery cell is filled more fully in the casing, and the space utilization rate is relatively high. However, since the battery is pressed tightly at the corners on both sides, it is prone to poor heat dissipation. Therefore, 0.1≤r*(a / b)≤2.9, the unit is rad. For example, r*(a / b) can be a range of 0.1, 0.5, 1, 1.5, 2, 2.9 or any two of them, the unit is rad.

[0053] In some embodiments, 1 ≤ r ≤ 3.2, where the unit is rad. For example, r can be 1, 2, 3, or 3.2, where the unit is rad.

[0054] In some embodiments, the length of the straight edge 120 of the housing is L, and the range of L / m is 0.4≤L / m≤0.95.

[0055] When batteries are assembled, the straight edge 120 of the casing is the surface where two adjacent batteries are in close contact. If L / m is less than the lower limit, it means the length of the long side is small, and the length of the curved side is large, which will affect the space utilization after battery assembly. If L / m exceeds the upper limit, it means the length of the long side is large, the contact surface between batteries is large, and the length of the curved side is small, which will be detrimental to heat dissipation. Therefore, the value of L / m should be moderate, for example, it can be 0.4, 0.5, 0.6, 0.9, 0.85 or any combination of two of these.

[0056] In some embodiments, 95≤L≤195, where the unit is mm. For example, L can be 95, 100, 150, or 195, where the unit is mm.

[0057] In some embodiments, the thickness of the arc edge is less than the thickness of the straight edge 120.

[0058] After the battery cells are wound or stacked and flattened, they become even more compact after being pressed at the edges, which increases the difficulty of heat dissipation. Therefore, it is necessary to improve the heat dissipation capacity at the edge of the cell to prevent excessive heat at the edge. Thus, a thinner design is adopted at the curved edge, which is beneficial for heat dissipation at the edge of the cell.

[0059] In some embodiments, 0.12 ≤ a / b ≤ 0.85.

[0060] When the thickness of the arc surface is smaller, heat dissipation is better, so the length of the arc edge can be appropriately reduced, thereby improving the space utilization rate after the battery pack is assembled. Therefore, 0.12≤a / b≤0.85. For example, a / b can be a range of 0.12, 0.2, 0.5, 0.6, 0.8, 0.85 or any two of them.

[0061] In some embodiments, the housing includes at least one battery cell, the battery cell including a straight section and an arcuate section, the arcuate section having a radius ratio of 0.9 to 1.1 to the arcuate edge of the housing.

[0062] In some embodiments, the housing contains only one battery cell.

[0063] In some embodiments, 0.4 ≤ L / m ≤ 0.92.

[0064] When the casing contains only one cell, the matching degree between the casing and the cell is more critical. After the single cell is wound and biased, the arc of the arc segment of the single cell will be larger than that of multiple cells stacked. Therefore, the arc edge of the casing needs to be appropriately increased to match the cell. Hence, 0.4≤L / m≤0.92; for example, L / m can be a range of 0.4, 0.5, 0.6, 0.8, 0.92 or any combination thereof.

[0065] In some embodiments, the battery cell includes a separator with a porosity ≥38% and 0.15≤a / b≤0.85.

[0066] A battery cell consists of a positive electrode and a negative electrode, with a separator located between them. These are wound or stacked to form the cell. During electrolyte filling, the electrolyte needs to gradually wet the entire cell through the separator and electrodes. At the edges of the cell, where the cell is more compacted after compression, wetting is less effective. When the separator has a high porosity, the wetting effect is better, especially at the battery edge. Therefore, it is not necessary to increase the length of the casing's arc edge to increase space and improve electrolyte wetting. Thus, the arc edge can be appropriately reduced, improving the space utilization of the battery pack. Therefore, 0.15 ≤ a / b ≤ 0.85. For example, the porosity can be 38%, 40%, 45%, 50%, etc., and a / b can be 0.15, 0.2, 0.35, 0.5, 0.6, 0.85, or any combination of two of these ranges.

[0067] In some embodiments, the opening is provided with a first cover plate and a second cover plate, and at least one of the first cover plate and the second cover plate is provided with a liquid injection hole. The liquid injection hole is located at a distance of h1 from one end of the cover plate and at a distance of h2 from the other end in the direction extending along the straight edge 120 of the housing, and 0.05≤h1 / h2≤20.

[0068] To ensure proper electrolyte wetting of the battery cell, the injection hole should be positioned as close to the center of the cover plate as possible to guarantee uniform wetting of the battery. However, since the cover plate needs to house the terminals and explosion-proof valve, the offset of the injection hole must be controlled. Therefore, the value of h1 / h2 should be moderate, for example, it can be a range of 0.05, 0.1, 0.5, 1, 5, 10, 20, or any combination thereof.

[0069] In some embodiments, the minimum thickness at the junction of the straight edge 120 and the arc edge of the housing is e, then 0.08mm≤e≤0.8mm. For example, e can be a range of 0.08, 0.1, 0.2, 0.5, 0.6, 0.8 or any two of them, in mm.

[0070] Secondly, this application proposes a battery pack comprising a plurality of batteries as described in the first aspect, with adjacent batteries being fitted together at a straight edge 120.

[0071] In the above embodiments, the battery pack of the second aspect includes the battery of the first aspect. Therefore, the battery pack of the second aspect has at least all the technical effects of the battery of the first aspect. The specific technical effects of the battery will not be described in detail here.

[0072] The embodiments of this application only illustrate the structure of the battery pack in relation to the improvement points of this application in the second aspect, but do not mean that it does not have other structures. For example, the battery pack also includes a battery frame for accommodating multiple batteries, and / or the battery pack also includes a protective shell for encapsulating multiple battery modules, etc. Other structures will not be described in detail here.

[0073] In some embodiments, the range of the battery casing straight edge length L / maximum casing length m is 0.4 ≤ L / m ≤ 0.9.

[0074] A higher L / m ratio indicates a longer straight edge (120°) and a shorter curved side edge. This results in greater space utilization when batteries are assembled. However, an excessively high ratio leads to a smaller curved side edge, which can interfere with the internal cells, squeezing them and causing lithium plating. Conversely, a low ratio results in a small straight edge (120°), reducing space utilization and affecting battery capacity. Therefore, the L / m value should be moderate, ideally ranging from 0.4, 0.5, 0.6, 0.8, 0.9, or any combination thereof.

[0075] In some embodiments, the gap between adjacent battery casing arc edges is d, where 0.1mm≤d≤5mm.

[0076] The curved edge is where the cell bends. These bends are tightly pressed together, making it easy for heat to accumulate and difficult to dissipate. A larger gap improves heat dissipation, but too large a gap results in low space utilization, while too small a gap negatively impacts heat dissipation. Therefore, the value of d should be appropriate. For example, d can be a range of 0.1, 0.5, 1, 3, 5, or any combination thereof, in mm.

[0077] In some embodiments, the battery pack further includes a liquid cooling plate, which is attached to the straight edge 120 of the battery housing, and the range of the length L of the straight edge 120 of the battery housing / the maximum length m of the housing is 0.42 ≤ L / m ≤ 0.95.

[0078] Liquid cooling plates are used to cool batteries and prevent them from overheating and causing thermal runaway. The larger the area that is in contact with the battery, the better the heat exchange effect. Therefore, 0.42≤L / m≤0.95. For example, L / m can be a range of 0.42, 0.5, 0.6, 0.7, 0.9, 0.95 or any combination thereof.

[0079] In particular, the term "and / or" in this application should be understood as follows:

[0080] In the first case, the term “and / or” located between the first subject and the second subject includes any of the following meanings: (1) only the first subject; (2) only the second subject; and (3) both the first subject and the second subject.

[0081] In the second case, the term "and / or" between the last two of three or more subjects means including at least any one of the subjects. For example, "first subject, second subject and / or third subject" has the same meaning as "first subject and / or second subject and / or third subject", specifically including the following combinations: (1) only the first subject; (2) only the second subject; (3) only the third subject; (4) the first subject and the second subject and no third subject; (5) the first subject and the third subject and no second subject; (6) the second subject and the third subject and no first subject; and (7) the first subject, the second subject and the third subject.

[0082] Furthermore, although the embodiments of this application have been described above in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the concept of this application, and such modifications and variations all fall within the scope of protection of this application.

Claims

1. A battery, characterized in that, Includes a housing (100) and a battery cell disposed inside the housing (100); The housing (100) is made of steel and has two opposite straight edges and two opposite arc edges. The two arc edges connect the two straight edges and surround to form a cavity for accommodating the battery cell. The housing has an opening oriented in the Z direction. The cross-sectional area of ​​the housing perpendicular to the Z direction is b, and the cross-sectional area of ​​the battery cell is a. The maximum length of the housing (100) cross-section is m, and the maximum width is n. Since c = m × n, then 0.2 ≤ a * c / b. 2 ≤20.

2. The battery according to claim 1, characterized in that, 0.1≤a / b≤0.

9.

3. The battery according to claim 1, characterized in that, The cross-sectional area b of the shell is in the range of 3848 mm. 2 ≤b≤37000mm 2 .

4. The battery according to claim 1, characterized in that, The cross-sectional area 'a' of the battery cell is in the range of 3675 mm². 2 ≤a≤14651mm 2 .

5. The battery according to claim 1, characterized in that, The arc of the shell (100) is r, and the range of r*(a / b) is 0.1≤r*(a / b)≤2.9, unit: rad.

6. The battery according to claim 1, characterized in that, The length of the straight side of the shell (100) is L, and the range of L / m is 0.4≤L / m≤0.

95.

7. The battery according to claim 1, characterized in that, The thickness of the arc edge is less than the thickness of the straight edge.

8. The battery according to claim 7, characterized in that, 0.12≤a / b≤0.

85.

9. The battery according to claim 6, characterized in that, The housing contains at least one of the battery cells, each battery cell comprising a straight section and an arc-shaped section, wherein the arc of the arc-shaped section is 0.9 to 1.1 times the arc of the arc edge of the housing.

10. The battery according to claim 9, characterized in that, The housing contains only one of the battery cells.

11. The battery according to claim 10, characterized in that, 0.4≤L / m≤0.

92.

12. The battery according to claim 1, characterized in that, The battery cell includes a separator with a porosity ≥38% and 0.15≤a / b≤0.

85.

13. The battery according to claim 1, characterized in that, The opening is provided with a first cover plate and a second cover plate. At least one of the first cover plate and the second cover plate is provided with a liquid injection hole. The liquid injection hole is located at a distance of h1 from one end of the cover plate and at a distance of h2 from the other end in the direction extending along the straight edge of the shell, where 0.05≤h1 / h2≤20.

14. The battery according to any one of claims 1 to 13, characterized in that, The minimum thickness at the junction of the straight edge and the arc edge of the shell (100) is e, then 0.08mm≤e≤0.8mm.

15. The battery according to any one of claims 1 to 13, characterized in that, 100mm≤m≤500mm, 15mm≤n≤80mm.

16. A battery pack, characterized in that, The battery includes any one of claims 1 to 15, wherein adjacent batteries are disposed in contact with each other along straight edges.

17. The battery pack according to claim 16, characterized in that, The range of the straight side length L of the battery casing / the maximum length m of the casing is 0.4 ≤ L / m ≤ 0.

9.

18. The battery pack according to claim 16, characterized in that, The gap between adjacent arc edges of the battery casing is d, where 0.1mm ≤ d ≤ 5mm.

19. The battery pack according to claim 16, characterized in that, The battery pack also includes a liquid cooling plate, which is attached to the straight edge of the battery housing. The range of the length L of the straight edge of the battery housing / the maximum length m of the housing is 0.42 ≤ L / m ≤ 0.95.

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