Battery shell

Abstract

The battery shell comprises a first wall and a second wall which are connected with each other, the included angle alpha between the first wall and the second wall is larger than or equal to 80 degrees and smaller than or equal to 120 degrees, the first wall is provided with a liquid injection hole, the second wall is provided with a plurality of grooves which are formed in the circumferential direction of the second wall at intervals, and the first wall and the second wall are connected with each other. The distance L1 between the liquid injection hole and the second wall and the distance L2 between the liquid injection hole and the two adjacent grooves meet the condition that L1 / L2 is larger than or equal to 32 and smaller than or equal to 3000. According to the battery shell, the liquid injection efficiency can be improved, and the groove can enlarge the capacity of the battery shell under the condition that the size of the battery shell is not changed, so that the energy density of the battery is improved.

Description

[0001] The application is a divisional application, the original application number is 202422747704.7, the original application date is November 11, 2024, the original application name is "Battery shell", and the original application is incorporated by reference in the application. TECHNICAL FIELD

[0002] The application relates to the technical field of lithium ion batteries, in particular to a battery shell. BACKGROUND

[0003] The application field of lithium batteries is very wide, covering many aspects from daily electronic products to large energy storage systems. The electrolyte of the lithium battery serves as the medium for charging and discharging, and its role is to conduct ions between the positive and negative electrodes. The injection is a key process in the production of lithium ion batteries, and the effect of the injection not only affects the performance of the battery, but also restricts the production efficiency. The injection is divided into two steps, the first is to inject the electrolyte into the battery, and the second is to soak, that is, the battery absorbs the electrolyte. Because the battery occupies a large space in the shell, the battery is in close contact with the shell, and the space provided by the electrolyte in the shell is limited. This makes the soaking process very time-consuming, causing great difficulty in the injection process. How to improve the injection efficiency is a problem to be solved. Utility model content

[0004] The battery shell provided by the application can improve the injection efficiency and the liquid storage capacity.

[0005] The battery shell provided by the application comprises a first wall and a second wall connected to each other, the included angle a between the first wall and the second wall satisfies 80°≤a≤120°, the first wall is provided with an injection hole, the second wall is provided with a plurality of grooves arranged along the circumferential direction of the second wall, the distance L1 between the injection hole and the second wall, and the distance L2 between adjacent two grooves satisfy: 32≤L1 / L2≤3000.

[0006] In the above embodiment, when the electrolyte is injected, the edge of the battery cell is prone to a liquid deficiency state, the grooves of the second wall can store electrolyte, so that the battery cell is soaked from the outside to the inside and from the inside to the outside at the same time, and the injection efficiency is improved. In the process of charging and discharging of the battery, the electrolyte stored in the grooves can also supplement the electrolyte for the battery cell. The setting of the grooves also increases the distance between the second wall and the battery cell, which can improve the injection efficiency. By comprehensively adjusting the relationship between the distance L1 between the injection hole and the second wall and the distance L2 between adjacent two grooves, the liquid storage capacity of the battery shell is improved, and the battery cell is well soaked. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1A structural schematic diagram of a battery shell provided for an embodiment of the present application;

[0008] Figure 2 A structural schematic diagram of a square shell battery provided for an embodiment of the present application;

[0009] Figure 3 A structural schematic diagram of another battery shell provided for an embodiment of the present application;

[0010] Figure 4 A structural schematic diagram of another battery shell provided for an embodiment of the present application;

[0011] Figure 5 A structural schematic diagram of another battery shell provided for an embodiment of the present application;

[0012] Figure 6 A structural schematic diagram of another battery shell provided for an embodiment of the present application.

[0013] Reference Signs:

[0014] 1 - second wall; 2 - first wall; 21 - top plate; 22 - bottom plate; 4 - liquid injection hole; 5 - groove; 11 - first sub-wall; 12 - second sub-wall; 51 - first sub-groove; 52 - second sub-groove; 53 - third sub-groove; 54 - fourth sub-groove; 55 - fifth flow guide groove; 56 - sixth flow guide groove. DETAILED DESCRIPTION

[0015] In order to make the objects, technical solutions and advantages of the present application clearer, the following further describes the present application with reference to the accompanying drawings.

[0016] The terms used in the following embodiments are only for the purpose of describing particular embodiments and are not intended to be limiting of the present application. As used in the specification and the appended claims, the singular forms "a," "an" and "the" are intended to include both singular and plural forms, unless the context clearly indicates otherwise.

[0017] Reference to "one embodiment" or "an embodiment" or "the embodiment" or "the

[0018] A lithium-ion battery consists of a battery casing and a battery cell housed within the casing, the cell being immersed in an electrolyte. The electrolyte's primary function is to act as a carrier for ion transport within the battery, conducting ions. The battery cell is mainly composed of a positive electrode, a negative electrode, and a separator wound together. The positive and negative electrode are positioned on opposite sides of the separator. During charging, lithium ions at the positive electrode are released and enter the electrolyte, then pass through the microporous structure of the separator, migrate to the negative electrode, and combine with electrons that have arrived at the negative electrode via an external circuit. In this process, lithium ions are released from the positive electrode material, enter the electrolyte, and migrate to the negative electrode under the influence of an external electric field, forming compounds with the carbon material of the negative electrode. During discharge, electrons and lithium ions move simultaneously, but via different paths. Electrons flow from the negative electrode to the positive electrode through the external circuit, while lithium ions enter the electrolyte from the negative electrode, pass through the separator, migrate to the positive electrode, and combine with electrons that have already arrived.

[0019] Electrolyte is injected into the battery casing through the injection port. Since the air inside the battery casing has been removed before injection, the electrolyte enters the casing relatively quickly. However, because the battery cell occupies a significant amount of space within the casing, and its outer periphery is tightly fitted to the casing, there is no space for electrolyte flow. The electrolyte can only flow into the cell through gaps in the center and gradually penetrates the electrode layers from the inside out via capillary action. This results in a longer immersion time and can also lead to poor immersion of the core, causing inconsistent electrical performance and capacity.

[0020] To address the aforementioned issues, this application provides a battery casing that improves liquid injection and wetting efficiency.

[0021] Figure 1 A schematic diagram of a battery casing provided for an embodiment of this application is shown below. Figure 1 As shown, an embodiment of this application provides a battery casing comprising: a first wall and a second wall 1 connected to each other, wherein the included angle α between the first wall and the second wall 1 satisfies 80°≤α≤120°, the first wall 2 is provided with an injection hole 4, and the second wall 1 is provided with a plurality of grooves 5 spaced apart along the circumferential direction of the second wall 1, wherein the distance L1 between the injection hole 4 and the second wall 1 and the distance L2 between the injection hole 4 and two adjacent grooves 5 satisfies: 32≤L1 / L2≤3000.

[0022] In the above embodiment, the injection hole 4 can be located at the center of the first wall 2. Electrolyte enters the battery casing through the injection hole 4. As the liquid level gradually rises, the electrolyte reaches the center of the battery cell and simultaneously enters and is stored in the groove 5. This allows the battery cell to be simultaneously wetted from both the outside in and the inside out, improving the injection efficiency. During battery charging and discharging, the electrolyte stored in the groove 5 can also replenish the battery cell. The groove 5 effectively increases the distance between the second wall 1 and the battery cell, further improving the injection efficiency.

[0023] By comprehensively adjusting the relationship between the distance L1 between the liquid injection hole 4 and the second wall 1 and the spacing L2 of the two adjacent grooves 5, 32≤L1 / L2≤3000, the liquid storage capacity of the battery shell is improved. When the electrolyte is injected, the edge of the battery cell is prone to liquid deficiency. The grooves 5 of the second wall 1 can store electrolyte, so that the battery cell is simultaneously infiltrated from two directions, i.e., from the outside to the inside and from the inside to the outside, to obtain a better infiltration effect and improve the liquid injection efficiency. The amount of injected liquid has a significant impact on the performance of the battery. An appropriate amount of electrolyte can ensure the full infiltration of the electrode material, allowing lithium ions to smoothly migrate between electrodes, thereby reducing internal resistance and improving the charge-discharge efficiency and cycle life of the battery.

[0024] In an embodiment, the depth a of the groove 5 and the thickness b of the battery shell satisfy 0

[0025] The energy density of the battery refers to the amount of energy stored in a unit volume or unit mass of the battery. Specifically, the energy density of the battery can be divided into weight energy density and volume energy density, with units of watt-hour / kilogram (Wh / kg) and watt-hour / liter (Wh / L), respectively. The calculation formula of the weight energy density is: battery capacity x discharge platform / weight, and the calculation formula of the volume energy density is: battery capacity x discharge platform / volume. The volume of the electrolyte in the battery occupies a certain proportion, especially for the volume energy density, the capacity of the electrolyte directly affects the overall energy density of the battery. Therefore, by increasing the capacity of the battery shell to increase the content of the electrolyte, the energy density of the lithium battery can be effectively improved, and the endurance and overall performance of the battery can be improved.

[0026] In an embodiment, the distance L1 between the liquid injection hole 4 and the second wall 1 satisfies 7mm≤L1≤200mm; the spacing L2 of the two adjacent grooves 5 satisfies 4mm≤L2≤20mm.

[0027] In an embodiment, the battery shell is a cylinder, i.e., the battery is a cylindrical battery, the distance L1 between the liquid injection hole 4 and the second wall 1 is the inner diameter of the cylinder, and 32≤L1 / L2≤700. Satisfying the above proportional relationship, the liquid storage capacity of the groove 5 is high, which is beneficial to the supply of electrolyte in the battery during the charge and discharge process.

[0028] In one embodiment, the distance L1 between the liquid injection hole 4 and the second wall 1 satisfies 7mm≤L1≤40mm, and the distance L2 between two adjacent grooves 5 satisfies 4mm≤L2≤20mm.

[0029] Figure 2 The structure of the prismatic battery is shown in the following figure. Figure 2 As shown in the figure, in one embodiment, the battery case is a quadrangular prism, i.e. the battery is a prismatic battery. The first wall 2 is rectangular, which includes a pair of long sides and a pair of short sides. The second wall 1 includes a pair of large side walls (i.e. the first sub-wall 11) and a pair of small side walls (i.e. the second sub-wall 12). The long sides are connected to the large side walls, and the short sides are connected to the small side walls. The distance L1 between the liquid injection hole 4 and the second wall 1 includes L11 and L12. L11 refers to the distance between the liquid injection hole 4 and the first sub-wall 11, and L12 refers to the distance between the liquid injection hole 4 and the second sub-wall 12. The distance L2 between two adjacent grooves 5 includes the distance L21 between two adjacent grooves 5 on the first sub-wall 11 and the distance L22 between two adjacent grooves 5 on the second sub-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 hole 4 and the first sub-wall 11 is small, the flow path of the electrolyte to the first sub-wall 11 is short, and the edge of the battery cell close to the first sub-wall 11 is less likely to be in a liquid deficiency state. Therefore, the distance between two adjacent grooves 5 on the first sub-wall 11 can be relatively large. The distance between the liquid injection hole 4 and the second sub-wall 12 is large, and the edge of the battery cell close to the second sub-wall 12 is prone to be in a liquid deficiency state. Therefore, the distance between two adjacent grooves 5 on the second sub-wall 12 can be relatively small, so that the second sub-wall 12 can store more electrolyte to supplement the edge of the battery cell close to the second sub-wall 12.

[0030] In further embodiments, the parameters L11 and L21 related to the first sub-wall 11 satisfy 8mm≤L11≤140mm and 5mm≤L21≤20mm. The parameters L12 and L22 related to the second sub-wall 12 satisfy 50mm≤L12≤200mm and 4mm≤L22≤15mm.

[0031] In one embodiment, the second wall 1 includes a top plate 21 and a bottom plate 22 arranged oppositely, the angle α between the first wall 2 and the second wall 1 is preferably 90°, and the liquid injection hole 4 is located on the top plate 21 or the bottom plate 22. It is worth noting that the positions of the top plate 21 and the bottom plate 22 are determined according to the placement posture of the battery, and the positions of the top plate 21 and the bottom plate 22 can be interchanged.

[0032] The width of the groove 5 cannot be too small, otherwise the liquid storage capacity and the ability to improve the electrolyte injection efficiency are low. The width of the groove 5 also cannot be too wide, otherwise it will have a greater impact on the structural strength of the battery shell. In a specific embodiment, the width c of the groove 5 satisfies: 0.5mm≤c≤15mm, the width of the groove 5 refers to the width of the slot. The width may, for example, be specifically 0.5mm, 1mm, 5mm, 10mm, 12mm, 15mm. The groove 5 satisfies the above condition to improve the injection efficiency and make the battery shell maintain good structural strength.

[0033] In an embodiment, the number N of the groove 5 satisfies: 2≤N≤20.

[0034] In an embodiment, the cross section of the groove 5 is semicircular or square, preferably semicircular. The electrolyte is generally composed of high-purity organic solvents, electrolyte lithium salts, and necessary additives. By setting the cross section of the groove 5 to be square or semicircular, the electrolyte can maintain good fluidity, thereby improving the injection efficiency.

[0035] In an embodiment, the first wall 2 can be provided with a plurality of second grooves (not shown in the figure), one end of each second groove can be in communication with one groove 5. The second grooves are distributed on the periphery of the injection hole 4. The electrolyte enters the battery shell from the injection hole 4, flows into the second grooves and flows along the second grooves to the periphery of the first wall 2, and then enters the groove 5. The second groove can accelerate the flow rate of the electrolyte from the injection hole 4 to the periphery of the battery shell. Avoid the situation that the battery core is tightly attached to the first wall, the electrolyte flows slowly to the periphery of the shell, and the injection efficiency is affected.

[0036] In a further embodiment, the end of the above-mentioned second groove away from the groove 5 can be connected with the injection hole 4, and the second grooves are arranged in a divergent pattern on the periphery of the injection hole 4, so that the electrolyte entering the battery shell can directly enter the second grooves, thereby accelerating the flow rate of the electrolyte to the periphery of the battery shell.

[0037] The groove 5 can include various forms, which will be introduced below.

[0038] Please continue to refer to Figure 1 In an embodiment, the above-mentioned groove 5 includes a first sub-groove 51, the extension direction of the first sub-groove 51 is perpendicular to the first wall, and the end of the first sub-groove 51 extends to the bottom plate 22. The injection hole 4 is located on the bottom plate 22. The first sub-groove 51 is a linear slot, which flows along a linear path during the rising of the liquid level of the electrolyte, has a fast flow rate, and can quickly fill the battery shell, thereby improving the injection efficiency.

[0039] Figure 3 Another structural schematic diagram of a battery shell provided for the embodiments of the present application is shown inFigure 3 As shown in another embodiment, the groove 5 comprises a second sub-groove 52, the edge where the bottom plate 22 intersects with the second wall 1 has an included angle β with the second sub-groove 52, and 11°≤β≤80° is satisfied. The second sub-groove 52 is also a linear groove, and it is different from the first sub-groove 51 that the second sub-groove 52 is arranged obliquely. The two ends of the second sub-groove 52 extend to the top plate 21 and the bottom plate 22 respectively. The length of the second sub-groove 52 is longer than that of the first sub-groove 51, so it can store more electrolyte and improve the energy density of the battery.

[0040] Figure 4 Another structural schematic diagram of a battery shell provided for an embodiment of the present application is shown in FIG. 6. Figure 4 As shown in another embodiment, the groove 5 comprises a plurality of third sub-grooves 53, and the plurality of third sub-grooves 53 are all perpendicular to the bottom plate 22. The plurality of third sub-grooves 53 are arranged at intervals in the direction perpendicular to the bottom plate 22, that is, the plurality of third sub-grooves 53 are located on the extension of the same straight line. Specifically, the number of third sub-grooves 53 located on the same straight line can be two, three, four, etc. Figure 4 An example is shown in FIG. 5, which shows two third sub-grooves 53 located on the same straight line. In the height direction of the battery, the two adjacent third sub-grooves 53 are spaced apart by a predetermined distance. The height direction of the battery also refers to the direction perpendicular to the bottom plate 22.

[0041] Figure 5 Another structural schematic diagram of a battery shell provided for an embodiment of the present application is shown in FIG. 6. Figure 5 As shown in another embodiment, the groove 5 comprises a plurality of fourth sub-grooves 54, and the plurality of fourth sub-grooves 54 are all perpendicular to the bottom plate 22. In the height direction of the battery, the plurality of fourth sub-grooves 54 are arranged at intervals. It is different from the third sub-groove 53 in the above embodiment that the plurality of fourth sub-grooves 54 are arranged staggered. That is, the plurality of fourth sub-grooves 54 are not located on the extension of the same straight line in the direction perpendicular to the bottom plate. The plurality of fourth sub-grooves 54 can be arranged in groups, and the number of fourth sub-grooves 54 in each group can be multiple. Figure 5 An example is shown in FIG. 6, which shows two fourth sub-grooves 54 arranged staggered in a group. There can be three, four, etc. fourth sub-grooves 54 in a group.

[0042] Figure 6 Another structural schematic diagram of a battery shell provided for an embodiment of the present application is shown in FIG. 6. Figure 6 As shown in a further embodiment, in a group of fourth sub-grooves 54 arranged staggered, a fifth flow guide groove 55 and a sixth flow guide groove 56 are included. One end of the fifth flow guide groove 55 close to the bottom plate 22 is located between two adjacent sixth flow guide grooves 56.

[0043] It is worth mentioning that the straight grooves in some of the above embodiments can be replaced by wavy grooves.

[0044] In one embodiment, the first wall 2 and the second wall 1 are connected by a chamfer. That is, the top plate 21 and the second wall 1 are connected by a chamfer, and the bottom plate 22 and the second wall 1 are connected by a chamfer. The groove 5 is located between the two chamfers, that is, the groove 5 is entirely located in the second wall 1 and does not extend to the chamfer position. In this way, the accumulation of electrolyte at the chamfer can be reduced.

[0045] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the present application. Thus, it is intended that the present application cover the modifications and changes as long as they come within the scope of the claims of the present application and their equivalents.

Claims

1. A battery case characterized by comprising: The battery shell is a quadrangular prism, comprising: a first wall and a second wall connected to each other, an included angle a of the first wall and the second wall satisfies 80°≤a≤120°, the first wall is provided with a liquid injection hole, the second wall is provided with a plurality of grooves arranged at intervals along a circumferential direction of the second wall, the first wall comprises a long side and a short side connected to each other, and the second wall comprises a first sub-wall and a second sub-wall, the first sub-wall is connected to the long side, and the second sub-wall is connected to the short side. A distance L1 of the liquid injection hole from the second wall comprises a distance L11 of the liquid injection hole from the first sub-wall and a distance L12 of the liquid injection hole from the second sub-wall, and a spacing L2 of adjacent two grooves comprises a spacing L21 of adjacent two grooves on the first sub-wall and a spacing L22 of adjacent two grooves on the second sub-wall. The distance L11 of the liquid injection hole from the first sub-wall and the spacing L21 of adjacent two grooves on the first sub-wall satisfy 40≤L11 / L21≤700, and the distance L12 of the liquid injection hole from the second sub-wall and the spacing L22 of adjacent two grooves on the second sub-wall satisfy 220≤L12 / L22≤3000. The number N of the grooves satisfies 2≤N≤20.

2. The battery case according to claim 1, wherein The distance L11 of the liquid injection hole from the first sub-wall satisfies 8mm≤L11≤140mm, the spacing L21 of adjacent two grooves on the first sub-wall satisfies 5mm≤L21≤20mm, the distance L12 of the liquid injection hole from the second sub-wall satisfies 50mm≤L12≤200mm, and the spacing L22 of adjacent two grooves on the second sub-wall satisfies 4mm≤L22≤15mm.

3. The battery case according to claim 1, wherein The depth a of the groove and the thickness b of the battery shell satisfy 0 4. The battery case of claim 1, wherein, The first wall comprises a top plate and a bottom plate arranged oppositely, and the liquid injection hole is located on the top plate or the bottom plate.

5. The battery case of claim 4, wherein, The top plate and the second wall are provided with a chamfer, the bottom plate and the second wall are provided with a chamfer, the groove is located between the two chamfers, and the groove does not extend to the chamfer position.

6. The battery case of claim 5, wherein, The groove comprises a first sub-groove, an extension direction of the first sub-groove is perpendicular to the bottom plate, and an end of the first sub-groove extends to the bottom plate, and the liquid injection hole is located on the bottom plate.

7. The battery case of claim 5, wherein, The groove comprises a second sub-groove, an edge of the bottom plate intersecting with the second wall has an included angle β with the second sub-groove, and the included angle β satisfies 11°≤β≤80°.

8. The battery case of claim 5, wherein, The groove comprises a plurality of third sub-grooves, the plurality of third sub-grooves are all perpendicular to the bottom plate, and the plurality of third sub-grooves are arranged at intervals in a direction perpendicular to the bottom plate.

9. The battery case of claim 5, wherein, The groove comprises a plurality of fourth sub-grooves, the plurality of fourth sub-grooves are all perpendicular to the bottom plate, and the plurality of fourth sub-grooves are arranged alternately in a direction perpendicular to the bottom plate.

10. The battery case of claim 1, wherein, The first wall is provided with a plurality of second grooves, and the second grooves communicate with the grooves.

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