Battery housing

Abstract

Battery housing characterized in that it has the following: a first wall and a second wall connected to each other, wherein an angle α between the first wall and the second wall satisfies: 80°≤α≤120°, a liquid injection opening is provided on the first wall, several grooves are provided on the second wall and are spaced apart along a circumferential direction of the second wall, and a distance L1 between the liquid injection opening and the second wall and a distance L2 between two adjacent grooves satisfies: 32≤L1 / L2≤3000.

Description

AREA OF TECHNOLOGY

[0001] The present application relates to the field of lithium-ion battery technology and in particular to a battery housing. BACKGROUND

[0002] Lithium batteries have a very wide range of applications, covering numerous aspects from everyday electronic products to large energy storage systems. The electrolyte in a lithium battery serves as the charging and discharging medium; its function is to conduct ions between a positive and a negative electrode. Liquid injection, a key process in the manufacture of lithium-ion batteries, not only affects battery performance but also limits production efficiency. Liquid injection consists of two steps: first, injecting the electrolyte into the battery, and second, wetting, i.e., the absorption of the electrolyte by a battery cell. Since the battery cell occupies a large proportion of the interior space of a casing, resulting in close contact between the cell and the casing, the space available for the electrolyte within the casing is limited.This makes the wetting process very time-consuming and causes major difficulties in the liquid injection process. Improving the efficiency of liquid injection is a pressing problem. SUMMARY

[0003] A battery housing provided by the present application is able to improve the efficiency of liquid injection and the capacity of liquid storage.

[0004] The present application provides a battery housing comprising: a first wall and a second wall connected to each other, wherein an angle α between the first wall and the second wall satisfies: 80°≤α≤120°, a liquid injection opening is provided on the first wall, several grooves are provided on the second wall and are spaced apart along a circumferential direction of the second wall, and a distance L1 between the liquid injection opening and the second wall and a distance L2 between two adjacent grooves satisfy: 32≤L1 / L2≤3000.

[0005] In the implementation described above, electrolyte injection tends to result in a fluid shortage at one edge of the battery cell. The grooves on the secondary wall can store electrolyte, allowing the battery cell to be wetted simultaneously from the outside in and from the inside out, thus improving the efficiency of the fluid injection. During charging and discharging, the electrolyte stored in the grooves can also replenish the battery cell. An arrangement of the grooves also indirectly increases the distance between the secondary wall and the battery cell, further improving the efficiency of the fluid injection.By comprehensively adjusting the ratio between the distance L1 from the liquid injection opening to the second wall and the distance L2 between two adjacent grooves, the liquid storage capacity of the battery casing is improved, resulting in better wetting of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a structural representation of a battery housing according to an embodiment of the present application; Fig. Figure 2 is a structural representation of a prismatic battery according to an embodiment of the present application; Fig. Figure 3 is a structural representation of another battery housing according to an embodiment of the present application; Fig. Figure 4 is a structural representation of another battery housing according to an embodiment of the present application; Fig. Figure 5 is a structural representation of another battery housing according to an embodiment of the present application; and Fig. Figure 6 is a structural representation of another battery housing according to an embodiment of the present application. Reference symbol:

[0006] 1-second wall; 2-first wall; 21-upper plate; 22-lower plate; 4-liquid injection port; 5-grooves; 11-first partial wall; 12-second partial wall; 51-first partial grooves; 52-second partial grooves; 53-third partial grooves; 54-fourth partial grooves; 55-fifth partial grooves; 56-sixth partial grooves. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0007] To clarify the purpose, technical solutions and advantages of the present application, the following detailed description of the present application is provided in conjunction with the attached drawings and embodiments.

[0008] The designations used in the following embodiments serve only to describe particular embodiments and are not intended to limit the present application. In the language used in the description and the attached claims of the present application, singular forms such as "a", "an", "the", "the aforementioned", "mentioned above" and "these" are also intended to include plural forms such as "one or more", unless expressly stated otherwise in the context.

[0009] References to “an embodiment” or “particular embodiments” as set forth in this description mean that particular features, structures, or properties described in connection with the embodiments are included in one or more embodiments of this application. Unless expressly stated otherwise in a specific case, the terms “comprise / include”, “contain”, “have”, and their variations mean “including, but not limited to”.

[0010] A lithium battery consists of a battery casing and a battery cell located within the casing, with the battery cell immersed in electrolyte. The main function of the electrolyte is to act as a carrier for ion transport within the battery and to conduct ions. The battery cell is primarily manufactured by winding positive electrode foils, negative electrode foils, and separators. The positive and negative electrode foils are positioned on either side of the separator. During charging, lithium ions are released from the positive electrode and enter the electrolyte, then permeate the microporous structure of the separator, migrate to the negative electrode, and combine with electrons flowing to the negative electrode via the external circuit.In this process, lithium ions detach from the positive electrode material, enter the electrolyte, and, under the influence of an external electric field, migrate to the negative electrode, where they bond with the carbon material of the negative electrode. During discharge, electrons and lithium ions move simultaneously, but along different paths. Electrons flow from the negative electrode through the external circuit to the positive electrode, while lithium ions enter the electrolyte from the negative electrode, migrate through the separator to the positive electrode, and combine with the electrons that have already arrived.

[0011] The electrolyte is injected into the battery casing through the liquid injection port. Since the air in the battery casing is removed before the liquid injection, the electrolyte can penetrate the interior of the casing relatively quickly. However, because the battery cell occupies a large space within the casing and is positioned close to the edge, leaving little room for electrolyte flow, the electrolyte can only enter the cell through the gap in its central position and gradually penetrate each layer of the electrode foils from the inside out via capillary action. This results in a longer wetting time and, due to insufficient cell wetting, can lead to poor electrical performance and capacity stability of the battery.

[0012] To solve the above problems, the battery housing provided by the embodiments of the present application can improve the efficiency of liquid injection and wetting.

[0013] Fig. Figure 1 is a structural representation of a battery housing according to an embodiment of the present application. A battery housing provided by an embodiment of the present application has, as shown in Fig. Figure 1 shows a first wall and a second wall 1 connected to each other, wherein an angle α between the first wall and the second wall 1 satisfies: 80°≤α≤120°, a liquid injection opening 4 is provided on the first wall 2, several grooves 5 are provided on the second wall 1 and are spaced apart along a circumferential direction of the second wall 1, and a distance L1 between the liquid injection opening 4 and the second wall 1 and a distance L2 between two adjacent grooves 5 satisfy: 32≤L1 / L2≤3000.

[0014] In the embodiment described above, the liquid injection port 4 can be located in the center of the first wall 2. The electrolyte enters the battery casing through the liquid injection port 4, and as the liquid level gradually rises, the electrolyte reaches a central position within the battery cell. Simultaneously, the electrolyte also enters and is stored in the multiple grooves 5. This allows the battery cell to be wetted simultaneously from the outside in and from the inside out, thus improving the efficiency of the liquid injection. During charging and discharging, the electrolyte stored in the grooves 5 can also replenish the battery cell. The arrangement of the grooves 5 also indirectly increases the distance between the second wall 1 and the battery cell, which can further improve the efficiency of the liquid injection.

[0015] By comprehensively adjusting the ratio between the distance L1 from the liquid injection port 4 to the second wall 1 and the distance L2 between two adjacent grooves 5 to ensure 32 ≤ L1 / L2 ≤ 3000, the liquid storage capacity of the battery casing is improved. During electrolyte injection, there is a tendency for liquid to be lacking at the edge of the battery cell. The grooves 5 on the second wall 1 can store electrolyte, allowing the battery cell to be wetted simultaneously from the outside in and the inside out, resulting in better wetting and improved liquid injection efficiency. The amount of liquid injected has a significant impact on battery performance.An appropriate amount of electrolyte ensures thorough wetting of the electrode materials, allowing lithium ions to move freely between the electrodes, thereby reducing internal resistance and improving the battery's charge-discharge efficiency and cycle stability.

[0016] In one embodiment, the depth a of each of the grooves 5 and the thickness b of the battery casing satisfy 0

[0017] ​The grooves (5) are also able to increase the capacity of the battery casing without changing its size, allowing the casing to hold more electrolyte and thus improving the battery's energy density. The thickness of the battery casing refers to the thickness of the first and second walls. The first and second walls can be of the same thickness.

[0018] The energy density of a battery refers to the amount of stored energy per unit volume or mass of the battery. Specifically, battery energy density can encompass gravimetric energy density and volumetric energy density, measured in watt-hours per kilogram (Wh / kg) and watt-hours per liter (Wh / L), respectively. Gravimetric energy density is calculated as: battery capacity × discharge plateau / weight, and volumetric energy density as: battery capacity × discharge plateau / volume. The electrolyte occupies a certain proportion of the battery's volume, which particularly affects the overall energy density in the form of the volumetric energy density. Therefore, increasing the capacity of the battery casing to accommodate more electrolyte can effectively improve the energy density of a lithium battery, thereby increasing its durability and overall performance.

[0019] In one embodiment, the distance L1 between the liquid injection opening 4 and the second wall 1 satisfies 7mm≤L1≤200mm; and the distance L2 between two adjacent grooves 5 satisfies 4mm≤L2≤20mm.

[0020] In one embodiment, the battery housing is a cylinder, i.e., the battery is a cylindrical battery in which the distance L1 between the liquid injection opening 4 and the second wall 1 is the inner diameter of the cylinder, and where: 32≤L1 / L2≤700. By maintaining this ratio, the grooves 5 have a high liquid storage capacity, which is advantageous for supplying the battery cell with electrolyte during charging and discharging.

[0021] In a particular embodiment, the distance L1 between the liquid injection opening 4 and the second wall 1 satisfies: 7mm≤L1≤40mm; and the distance L2 between two adjacent grooves 5 satisfies: 4mm≤L2≤20mm.

[0022] Fig. Figure 2 is a structural representation of a prismatic battery according to an embodiment of the present application. As in Fig. As shown in Figure 2, in one embodiment the battery housing is a quadrilateral prism, i.e., the battery is a prismatic battery. The first wall 2 is rectangular and has two long edges and two short edges, and the second wall 1 has two large side walls (i.e., first partial walls 11) and two small side walls (i.e., second partial walls 12), with the long edges connected to the large side walls and the short edges connected to the small side walls. The distance L1 between the liquid injection port 4 and the second wall 1 has L11 and L12, where L11 refers to the distance from the liquid injection port 4 to the first partial wall 11 and L12 refers to the distance from the liquid injection port 4 to the second partial wall 12.The distance L2 between two adjacent grooves 5 corresponds to the distance L21 between two adjacent grooves 5 on the first partial wall 11 and the distance L22 between two adjacent grooves 5 on the second partial wall 12. L11 and L21 satisfy 40≤L11 / L21≤700, and L12 and L22 satisfy 220≤L12 / L22≤3000. The distance between the liquid injection port 4 and the first partial wall 11 is relatively small, resulting in a shorter flow path for the electrolyte to reach the first partial wall 11. This reduces the likelihood of a fluid shortage occurring at the edge of the battery cell near the first partial wall 11, which is why the distance between the grooves 5 on the first partial wall 11 can be relatively larger.The distance from the liquid injection opening 4 to the second partial wall 12 is larger, which makes the edge of the battery cell near the second partial wall 12 susceptible to liquid depletion, so that the distance between the grooves 5 on the second partial wall 12 can be provided relatively smaller, which allows the second partial wall 12 to store more electrolyte to fill the edge of the battery cell near the second partial wall 12.

[0023] In another embodiment, the following applies to the parameters of the first partial wall 11 for L11 and L21: 8 mm ≤ L11 ≤ 140 mm and 5 mm ≤ L21 ≤ 20 mm. Regarding the parameters of the second partial wall 12, the following applies to L12 and L22: 50 mm ≤ L12 ≤ 200 mm and 4 mm ≤ L22 ≤ 15 mm.

[0024] In one embodiment, the second wall 1 has an upper plate 21 and a lower plate 22 arranged opposite each other, wherein the angle α between the first wall 2 and the second wall 1 is preferably 90°, and wherein the liquid injection opening 4 is located either on the upper plate 21 or on the lower plate 22. It should be noted that the positions of the upper plate 21 and the lower plate 22 are determined by the installation position of the battery and can be interchanged.

[0025] The width of the grooves 5 should not be too small, as this would result in a low fluid storage capacity and reduced efficiency in improving electrolyte injection. The width of the grooves 5 should also not be too large, as this could significantly impair the static strength of the battery housing. In a particular embodiment, the width c of each of the grooves 5 satisfies the following: 0.5 mm ≤ c ≤ 15 mm, where the width of the grooves 5 refers to the width of the groove opening. This width could, in particular, be 0.5 mm, 1 mm, 5 mm, 10 mm, 12 mm, or 15 mm. If the grooves 5 meet these conditions, this can improve the injection performance while maintaining good static strength of the battery housing.

[0026] In one embodiment, the number N of grooves satisfies 5: 2≤N≤20.

[0027] In one embodiment, the cross-sections of the grooves 5 are semicircular or rectangular, preferably semicircular. The electrolyte generally consists of high-purity organic solvents, lithium salt electrolytes, and necessary additives. By selecting rectangular or semicircular cross-sections for the grooves 5, the electrolyte can flow more freely, which improves the injection efficiency.

[0028] In one embodiment, the first wall 2 can have several second grooves (not shown in the figure), with one end of each second groove communicating with one of the grooves 5. These second grooves are distributed around the liquid injection port 4. The electrolyte enters the battery casing through the liquid injection port 4, flows into the second grooves, and moves along them toward the edge of the first wall 2 before entering the grooves 5. The second grooves can accelerate the flow of electrolyte from the liquid injection port 4 to the surrounding areas of the battery casing. This prevents tight contact between the battery cell and the first wall from causing a slow electrolyte flow to the edge of the casing, which would impair injection efficiency.

[0029] In another embodiment, the end of the second grooves facing away from the grooves 5 can be connected to the liquid injection port 4, wherein the second grooves form a radial pattern around the liquid injection port 4, which allows the electrolyte to enter directly into the second grooves after entering the battery housing, thus accelerating the electrolyte flow to the edge of the battery housing.

[0030] The grooves 5 can take on various forms, and the following explanations address several different forms of the grooves 5.

[0031] It will be revisited Fig. Reference is made to Figure 1. In one embodiment, the grooves 5 have first partial grooves 51, wherein one direction of each of the first partial grooves 51 is perpendicular to the first wall and one end of each of the first partial grooves 51 extends to the lower plate 22. The liquid injection port 4 is located on the lower plate 22. The first partial grooves 51 are straight grooves, and the electrolyte can flow in a straight path during a rise in the liquid level, resulting in a higher flow rate and faster filling of the battery casing and improving the efficiency of the injection process.

[0032] Fig. Figure 3 is a structural representation of another battery housing according to one embodiment of the present application. In another embodiment, as in Fig. As shown in Figure 3, the grooves 5 have second sub-grooves 52, and an angle β between an edge where the lower plate 22 intersects the second wall 1, and the second sub-grooves 52 is 11° ≤ β ≤ 80°. The second sub-grooves 52 are also straight grooves, but unlike the first sub-grooves 51, the second sub-grooves 52 are arranged obliquely. The two ends of each of the second sub-grooves 52 extend to the upper plate 21 and the lower plate 22, respectively. The second sub-grooves 52 are longer than the first sub-grooves 51; therefore, the second sub-grooves 52 can store more electrolyte and improve the energy density of the battery.

[0033] Fig. Figure 4 is a structural representation of another battery housing according to one embodiment of the present application. In another embodiment, as in Fig. As shown in Figure 4, the grooves 5 have several third-part grooves 53, all of which run perpendicular to the lower plate 22. The several third-part grooves 53 are spaced apart along the direction perpendicular to the base plate 22; in other words, several third-part grooves 53 lie on the extension of the same straight line. The number of third-part grooves 53 on the same straight line can be, in particular, two, three, four, etc. Fig. Figure 4 shows, for illustration, two third partial grooves 53 on the same straight line. Along the vertical direction of the battery, two adjacent third partial grooves 53 have a preset distance from each other. The vertical direction of the battery is also referred to as the direction perpendicular to the lower plate 22.

[0034] Fig. Figure 5 is a structural representation of another battery housing according to one embodiment of the present application. In another embodiment, as in Fig. As shown in Figure 5, the grooves 5 have several fourth-part grooves 54, all of which run perpendicular to the lower plate 22, and several fourth-part grooves 54 are spaced apart from each other along the vertical direction of the battery. Unlike the third-part grooves 53 in the embodiment above, the several fourth-part grooves 54 are arranged in an offset pattern. That is, several fourth-part grooves 54 are not arranged on the extension of the same straight line along the direction perpendicular to the lower plate. Several fourth-part grooves 54 can be arranged in groups, with each group containing several fourth-part grooves 54. Fig. Figure 5 illustrates two offset fourth partial grooves 54 in a group. A group can also contain three, four, or more fourth partial grooves 54.

[0035] Fig. Figure 6 is a structural representation of another battery housing according to one embodiment of the present application. In a further embodiment, as shown in Fig. As shown in Figure 6, within a group of offset fourth partial grooves 54 there are fifth flow grooves 55 and sixth flow grooves 56. The end of the fifth flow grooves 55 near the lower plate 22 is located between two adjacent sixth flow grooves 56.

[0036] It should be noted that in some of the above-mentioned embodiments, the straight grooves can be replaced by wavy grooves.

[0037] In one embodiment, chamfered edges are provided at the junction between the first wall 2 and the second wall 1. Specifically, chamfered edges are provided between the upper plate 21 and the second wall 1, as well as between the lower plate 22 and the second wall 1. The multiple grooves 5 interlock between the two chamfered edges; that is, the multiple grooves 5 are located entirely on the second wall 1 and do not extend to the position of a chamfered edge. This reduces the accumulation of electrolyte in the chamfered areas.

[0038] Naturally, a person skilled in the art can make various modifications and variations to the present application without deviating from the fundamental concept and scope of the present application. If these changes and variations of the present application fall within the scope of protection of the claims and their equivalent technologies, then the present application shall also encompass these changes and variations.

Claims

[1] Battery casing, characterized by , that it has the following: a first wall and a second wall connected to each other, wherein an angle α between the first wall and the second wall satisfies: 80°≤α≤120°, a liquid injection opening is provided on the first wall, several grooves are provided on the second wall and are spaced apart along a circumferential direction of the second wall, and a distance L1 between the liquid injection opening and the second wall and a distance L2 between two adjacent grooves satisfies: 32≤L1 / L2≤3000. [2] Battery housing according to claim 1, characterized by , that the distance L1 between the liquid injection opening and the second wall satisfies: 7mm≤L1≤200mm; and the distance L2 between two adjacent grooves satisfies: 4mm≤L2≤20mm. [3] Battery housing according to claim 1 or 2, characterized by, that a depth a of each of the grooves and a thickness b of the battery casing satisfy: 0 [4] Battery housing according to any one of the preceding claims, characterized by , that the battery casing is a cylinder, and 32≤L1 / L2≤700. [5] Battery housing according to claim 4, characterized by , that the distance L1 between the liquid injection opening and the second wall satisfies: 7mm≤L1≤40mm; and the distance L2 between two adjacent grooves satisfies: 4mm≤L2≤20mm. [6] Battery housing according to any one of the preceding claims, characterized by ​, that the battery casing is a square prism, the first wall has a long edge and a short edge connected to each other, the second wall has a first partial wall and a second partial wall, the first partial wall is connected to the long edge and the second partial wall is connected to the short edge; the distance L1 between the liquid injection opening and the second wall has: a distance L11 between the liquid injection opening and the first partial wall and a distance L12 between the liquid injection opening and the second partial wall; and the distance L2 between two adjacent grooves has: a distance L21 between two adjacent grooves on the first partial wall and a distance L22 between two adjacent grooves on the second partial wall; wherein the distance L11 between the liquid injection opening and the first partial wall and the distance L21 between two adjacent grooves on the first partial wall satisfy: 40≤L11 / L21≤700; and wherein the distance L12 between the liquid injection opening and the second partial wall and the distance L22 between two adjacent grooves on the second partial wall satisfy: 220≤L12 / L22≤3000. [7] Battery housing according to any one of the preceding claims, characterized by that the first wall has an upper plate and a lower plate arranged opposite each other, and the liquid injection port is located on the upper plate or the lower plate. [8] Battery housing according to claim 7, characterized by, that the grooves have first partial grooves, a direction of each of the first partial grooves runs perpendicular to the lower plate and an end of each of the first partial grooves extends to the lower plate and the liquid injection opening is located on the lower plate. [9] Battery housing according to claim 7, characterized by , that the grooves have second partial grooves and an angle β between an edge where the lower plate cuts the second wall, and the second partial grooves is satisfied: 11°≤β≤80°. [10] Battery housing according to claim 7, characterized by that the grooves have several third partial grooves, each of the several third partial grooves is perpendicular to the lower plate, and the several third partial grooves are spaced apart along a direction perpendicular to the lower plate. [11] Battery housing according to claim 7, characterized bythat the grooves have several fourth partial grooves, each of the several fourth partial grooves is perpendicular to the lower plate, and the several fourth partial grooves are offset along a direction perpendicular to the lower plate. [12] Battery housing according to any one of the preceding claims, characterized by that several second grooves are provided on the first wall and that the second grooves are connected to the several grooves.

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