Battery cell shell and battery cell

Abstract

The present application relates to the field of battery technology, and in particular to a battery cell shell and a battery cell. The battery cell shell includes a shell and a cover plate. The cover plate is provided on one side of the shell in a first direction so that the shell and the cover plate enclose a closed space for accommodating an electrode group. The cover plate is provided with an explosion-proof valve. A protrusion assembly is provided on the inner side wall of the shell near the cover plate. In the first direction, the protrusion assembly is provided between the cover plate and the electrode group. The tensile coefficient that the electrode group can withstand is defined as δ. When the electrode group is pressed against the protrusion assembly, the contact area between the protrusion assembly and the electrode group is S. When the battery cell is in a thermal runaway state, the impact force of the gas in the closed space on the electrode group in the first direction is F, where δ×S>1.5F. According to the battery cell shell and battery cell provided by the present application, the electrode group is prevented from blocking the explosion-proof valve. In the case of thermal runaway of the battery cell, the gas inside the shell can be smoothly discharged through the explosion-proof valve, thereby ensuring the safety of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell casing and a battery cell. Background Art

[0002] Lithium-ion batteries have become the representative of modern high-performance batteries due to their advantages such as high operating voltage, high specific energy, large capacity, low self-discharge, good cycle performance, long service life, light weight and small size.

[0003] Today's battery cells typically consist of a housing, a cover, a lower plastic component, and a pole group. The housing and cover together enclose the pole group, with the lower plastic component located on the side of the cover facing the pole group. An explosion-proof valve is typically installed on the cover to allow high-pressure gas inside the housing to escape. The battery cell is primarily held in place by the lower plastic component, which presses against the pole group.

[0004] However, the insulating material used to make the lower plastic is typically plastic (such as PP), which has a low melting point. When a battery experiences thermal runaway, the internal temperature of the cell rises rapidly, and the lower plastic's restraining function on the electrode assembly can easily fail due to melting. This causes the electrode assembly to be easily pressed against the inner side of the cover plate by the impact of the high-pressure airflow inside the housing, causing the electrode assembly to block the explosion-proof valve, thereby affecting the valve's venting smoothness, reducing the valve's exhaust efficiency, and degrading the battery cell's safety. Summary of the Invention

[0005] The present application aims to provide a battery cell housing and battery cell, which, to a certain extent, address the existing technical problem that the insulating material used to make the lower plastic is generally made of plastic with a low melting point. When the battery experiences thermal runaway, as the temperature inside the battery cell rises sharply, the lower plastic part's limiting effect on the electrode group is easily lost due to the melting of the lower plastic part. This makes it very easy for the electrode group to be pressed against the inner side of the cover plate under the impact of the high-pressure airflow inside the housing, thereby causing the electrode group to block the explosion-proof valve, thereby affecting the smoothness of the explosion-proof valve's exhaust, reducing the exhaust effect of the explosion-proof valve, and reducing the safety performance of the battery cell.

[0006] According to a first aspect of the present application, a battery cell casing is provided, comprising a shell portion and a cover plate, wherein the cover plate is arranged on one side of the shell portion in a first direction, so that the shell portion and the cover plate together form a closed space for accommodating an electrode group, and the cover plate is provided with an explosion-proof valve;

[0007] A protrusion component is provided on the inner side wall of the shell portion close to the cover plate, and in the first direction, the protrusion component is provided between the cover plate and the pole group;

[0008] The tensile coefficient that the electrode group can withstand is defined as δ. When the electrode group is pressed toward the protruding assembly, the contact area between the protruding assembly and the electrode group is S. When the battery cell is in a thermal runaway state, the impact force of the gas in the enclosed space on the electrode group in the first direction is F, where δ×S>1.5F.

[0009] Preferably, the protrusion assembly includes a protrusion row formed by a plurality of protrusions spaced apart along the circumferential direction of the shell portion, and the ends of the plurality of protrusions in the same protrusion row facing the pole group in the first direction are aligned with each other.

[0010] Preferably, the protrusion assembly comprises one or more rows of protrusions;

[0011] When the protrusion assembly includes a plurality of protrusion rows, the protrusions of the plurality of protrusion rows are staggered in the first direction.

[0012] Preferably, the dimension of the protrusion in the circumferential direction of the shell is defined as a, the height of the protrusion protruding toward the enclosed space relative to the inner wall of the shell is defined as h, the number of protrusions included in each protrusion row is defined as n, and the number of protrusion rows is defined as b, wherein the contact area S between the protrusion assembly and the pole group is defined as ahnb.

[0013] Preferably, when the battery cell is in a thermal runaway state, the impact force F exerted on the electrode group in the first direction by the gas in the enclosed space is in a range of 120N to 300N.

[0014] Preferably, the tension coefficient δ that the pole group can withstand is in the range of 0.8N / mm 2 ~2.5N / mm 2 .

[0015] Preferably, a plastic part is further included, which is arranged on a side of the cover plate facing the electrode group, and when the cover plate and the shell are covered with each other, at least a portion of the plastic part extends into the enclosed space.

[0016] Preferably, in the first direction, the distance between the end of the protrusion assembly close to the pole group and the end of the shell close to the cover plate is less than or equal to the size of the portion of the plastic part extending to the enclosed space.

[0017] Preferably, the side wall of the plastic part is provided with an avoidance groove, and when the cover plate and the shell portion are covered with each other, the protrusion assembly is arranged in the avoidance groove.

[0018] According to a second aspect of the present application, a battery cell is provided, comprising the battery cell shell described in any of the above technical solutions, and thus having all the beneficial technical effects of the battery cell shell, which will not be described in detail herein.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The battery cell shell provided in the present application, when the protrusion assembly meets δ×S>1.5F, the protrusion assembly can effectively limit the electrode group, so that the electrode group can still remain without obvious movement when the battery cell is impacted by internal gas due to thermal runaway, thereby effectively avoiding the electrode group blocking the explosion-proof valve and causing danger. In addition, in the case of thermal runaway of the battery cell, the gas inside the shell can be smoothly discharged through the explosion-proof valve, thereby ensuring the safety of the battery cell.

[0021] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 A schematic diagram of the axonometric structure of a battery cell housing provided in an embodiment of the present application;

[0024] Figure 2 for Figure 1 An enlarged structural schematic diagram of the battery cell shell at point A is provided.

[0025] Reference numerals:

[0026] 1-cover plate; 111-first pole; 112-second pole; 12-explosion-proof valve; 2-plastic part; 21-avoidance groove; 3-shell; 31-protrusion.

[0027] F1-first direction; F2-second direction; F3-third direction. DETAILED DESCRIPTION

[0028] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0029] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application.

[0030] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0031] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0033] Refer to the following Figure 1 and Figure 2 The present invention describes a battery cell casing and a battery cell according to some embodiments of the present application.

[0034] See also Figure 1 and Figure 2 As shown, an embodiment of the first aspect of the present application provides a battery cell shell, which includes a shell portion 3 and a cover plate 1, and the cover plate 1 is covered on one side of the shell portion 3 in the first direction F1, so that the shell portion 3 and the cover plate 1 together form a closed space for accommodating the pole group, and the cover plate 1 is provided with an explosion-proof valve 12. A protrusion assembly is provided on the inner side wall of the shell portion 3 close to the cover plate 1, and in the first direction F1, the protrusion assembly is provided between the cover plate 1 and the pole group. The tensile coefficient that the pole group can withstand is defined as δ. When the pole group is pressed against the protrusion assembly, the contact area between the protrusion assembly and the pole group is S. When the battery cell is in a thermal runaway state, the pole group is subjected to an impact force F from the gas in the closed space in the first direction F1, wherein δ×S>1.5F.

[0035] Referring to Table 1, it shows that under the structure of the shell portion 3 of the same size, different sizes of protrusion components are selected, and 5 samples are trial-produced for each size of the protrusion component. They are assembled with the electrode group respectively to test the limiting effect of the protrusion component on the electrode group in the environment of thermal runaway exhaust after the assembled battery cell.

[0036] Table 1:

[0037]

[0038]

[0039] It can be seen from this that when the protrusion assembly meets δ×S>1.5F, the protrusion assembly can effectively limit the electrode group, so that the electrode group can still remain without obvious movement when the battery cell is thermally runaway and impacted by internal gas, thereby effectively avoiding the electrode group blocking the explosion-proof valve 12 and causing danger, and in the case of thermal runaway of the battery cell, the gas inside the shell 3 can be smoothly discharged through the explosion-proof valve 12, thereby ensuring the safety of the battery cell.

[0040] like Figure 1 As shown, F1 shown in the figure can be an example of the first direction F1. For ease of description, two directions intersecting each other on a plane perpendicular to the first direction F1 are defined as a second direction F2 and a third direction F3, respectively. F2 shown in the figure can be an example of the second direction F2, and F3 shown in the figure can be an example of the third direction F3. Taking the example of the housing structure shown in the figure being applicable to a prismatic battery cell, preferably, the first direction F1 can be the length direction of the prismatic battery cell, the second direction F2 can be the width direction of the prismatic battery cell, and the third direction F3 can be the thickness direction of the prismatic battery cell.

[0041] Preferably, if Figure 1 As shown, the protrusion assembly may include a protrusion row formed by a plurality of protrusions 31 spaced apart along the circumferential direction of the shell 3, and the ends of the plurality of protrusions 31 in the same protrusion row facing the pole group in the first direction F1 are aligned with each other, so that the protrusion row can simultaneously abut the pole group in the circumferential direction, thereby effectively increasing the abutment area between the protrusion row and the pole group during the process of thermal runaway exhaust of the battery cell, thereby preventing the pole group from being damaged during the process of thermal runaway exhaust of the battery cell.

[0042] Preferably, if Figure 1 and Figure 2 As shown, the figure shows an example in which the above-mentioned protrusion assembly includes two rows of protrusion rows. Preferably, in the first direction F1, the protrusions 31 of the two rows of protrusion rows are staggered to avoid the situation in which when one of the two rows of protrusion rows close to the pole group fails to limit the pole group, the battery cell shell can be limited by the other of the two rows of protrusion rows.

[0043] However, it is not limited to this. The number of protrusion rows included in the above-mentioned protrusion assembly is not limited to the above-mentioned two examples. As long as the positioning of the protrusion assembly to the pole group can be guaranteed, the number of protrusion rows included in the above-mentioned protrusion assembly can also be 1, 3, 4... or more.

[0044] Preferably, if Figure 1 As shown, in the same protrusion array, the distance between two adjacent protrusions 31 in the circumferential direction may be greater than the size of the protrusion 31 in the circumferential direction, so as to further ensure smooth exhaust of the gas inside the battery core shell 3 .

[0045] Preferably, if Figure 1 and Figure 2 As shown, taking the above-mentioned protrusion 31 as a rectangular parallelepiped as an example, the size of the protrusion 31 in the circumferential direction of the shell 3 is defined as a, the height of the protrusion 31 protruding into the enclosed space relative to the inner wall of the shell 3 is h, the number of protrusions 31 included in each protrusion row is n, and the number of protrusion rows is b, wherein the contact area between the protrusion assembly and the pole group is S=ahnb.

[0046] Preferably, if Figure 1 and Figure 2 As shown, the connection between the side walls of the protrusion 31 is provided with a chamfer to reduce the damage of the protrusion 31 to the electrode group during the process of limiting the electrode group.

[0047] Preferably, when the battery cell is in a thermal runaway state, the impact force F exerted on the electrode group in the first direction F1 by the gas in the enclosed space may be in the range of 120N to 300N, so as to adapt to the current battery cell thermal runaway environment.

[0048] Preferably, the tension coefficient δ that the pole group can withstand can be in the range of 0.8N / mm 2 ~2.5N / mm 2 , to adapt to the structure of the current pole group.

[0049] In an embodiment, preferably, Figure 1 and Figure 2 As shown, the battery cell shell may further include a plastic part 2, which is arranged on the side of the cover plate 1 facing the pole group, and when the cover plate 1 and the shell portion 3 are covered with each other, at least a portion of the plastic part 2 extends into the enclosed space. In this way, on the one hand, the plastic part 2 effectively achieves insulation between the explosion-proof cover and the pole group; on the other hand, by at least a portion of the plastic part 2 extending into the enclosed space, when the battery cell is in normal use, the pole group is limited by the plastic part 2, thereby further ensuring the stability of the pole group in use.

[0050] Preferably, in the first direction F1, the distance between the end of the protruding component close to the pole group and the end of the shell 3 close to the cover plate 1 (e.g. Figure 2 L1 shown) is less than or equal to the size of the portion of the plastic part 2 extending into the enclosed space (such as Figure 2 L2 is shown, so that when the cover plate 1 and the shell 3 cover each other, in the first direction F1, the protrusion assembly and the plastic part 2 are overlapped, so as to save space of the battery cell housing in the first direction F1.

[0051] Preferably, if Figure 1 and Figure 2 As shown, the side wall of the plastic part 2 can be provided with an avoidance groove 21. When the cover plate 1 and the shell 3 cover each other, the protrusion component is arranged in the avoidance groove 21 to further improve the space utilization of the above-mentioned battery cell shell.

[0052] Preferably, if Figure 1 and Figure 2 As shown, the avoidance groove 21 may extend along the first direction F1 and be open at one end of the plastic part 2 facing the electrode group, so as to facilitate assembly of the shell 3 and the plastic part 2 .

[0053] The embodiment of the second aspect of the present application further provides a battery cell, comprising the battery cell shell described in any of the above embodiments, and thus having all the beneficial technical effects of the battery cell shell, which will not be repeated here.

[0054] Preferably, if Figure 1 and Figure 2 As shown, the battery cell may further include a first electrode 111 and a second electrode 112 .

[0055] Preferably, if Figure 1 As shown, the first pole 111 and the second pole 112 can be respectively arranged on both sides of the battery cell.

[0056] Optionally, the first pole 111 may be provided on the cover plate 1 .

[0057] Optionally, the second pole 112 may be provided on the cover plate 1 .

[0058] However, the present invention is not limited thereto and, as not shown in the drawings, both the first pole and the second pole may be disposed on the cover plate, or both the first pole and the second pole may be disposed on a side of the shell away from the cover plate.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell shell, characterized in that: The device comprises a shell and a cover plate, wherein the cover plate is arranged on one side of the shell in the first direction so that the shell and the cover plate together form a closed space for accommodating the electrode group, and the cover plate is provided with an explosion-proof valve; A protrusion component is provided on the inner side wall of the shell portion close to the cover plate, and in the first direction, the protrusion component is provided between the cover plate and the pole group; The tensile coefficient that the electrode group can withstand is defined as δ. When the electrode group is pressed against the protrusion assembly, the contact area between the protrusion assembly and the electrode group is S. When the battery cell is in a thermal runaway state, the impact force of the gas in the confined space on the electrode group in the first direction is F, where δ×S>1.5F, and the unit of δ is N / mm 2 , the unit of S is mm 2 , the unit of F is N.

2. The battery cell housing according to claim 1, wherein: The protrusion assembly includes a protrusion row formed by a plurality of protrusions spaced apart along the circumferential direction of the shell, and ends of the plurality of protrusions in the same protrusion row facing the pole group in the first direction are aligned with each other.

3. The battery cell shell according to claim 2, characterized in that: The protrusion assembly includes one or more rows of protrusion rows; When the protrusion assembly includes a plurality of protrusion rows, the protrusions of the plurality of protrusion rows are staggered in the first direction.

4. The battery cell housing according to claim 3, wherein: Define the dimension of the protrusion in the circumferential direction of the shell as a, the height of the protrusion protruding into the enclosed space relative to the inner wall of the shell as h, the number of protrusions included in each protrusion row as n, and the number of protrusion rows as b, wherein the contact area S between the protrusion assembly and the pole group is ahnb.

5. The battery cell casing according to claim 1, wherein: When the battery cell is in a thermal runaway state, the electrode group is subjected to an impact force F in the first direction from the gas in the enclosed space in a range of 120N to 300N.

6. The battery cell casing according to claim 1, characterized in that: The tension coefficient δ that the electrode group can withstand is in the range of 0.8 to 2.

5.

7. The battery cell casing according to any one of claims 1 to 6, characterized in that: It also includes a plastic part, which is arranged on a side of the cover plate facing the pole group, and when the cover plate and the shell are covered with each other, at least a part of the plastic part extends into the enclosed space.

8. The battery cell casing according to claim 7, characterized in that: In the first direction, the distance between the end of the protrusion component close to the pole group and the end of the shell close to the cover plate is less than or equal to the size of the portion of the plastic part extending to the enclosed space.

9. The battery cell casing according to claim 7, characterized in that: The side wall of the plastic part is provided with an avoidance groove, and when the cover plate and the shell part are covered with each other, the protrusion component is arranged in the avoidance groove.

10. A battery cell, characterized in that: A battery cell casing comprising the battery cell casing according to any one of claims 1 to 9.

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