Battery cell shell and battery cell

Abstract

The invention relates to the technical field of batteries, in particular to a battery cell shell and a battery cell, the battery cell shell comprises a shell part and a cover plate, the cover plate covers one side of the shell part in a first direction, so that the shell part and the cover plate define a closed space for accommodating a pole group, and the cover plate is provided with an anti-explosion valve. A protruding assembly is arranged on the inner side wall, close to the cover plate, of the shell part, and the protruding assembly is arranged between the cover plate and the pole group in the first direction. The tensile force coefficient which can be borne by the pole group is defined as delta, the contact area between the bulge component and the pole group is S when the pole group presses the bulge component, the impact force of gas in the closed space on the pole group in the first direction is F when the battery cell is in a thermal runaway state, and delta * S is greater than 1.5 F. According to the battery cell shell and the battery cell provided by the invention, the explosion-proof valve is prevented from being blocked by the pole group, gas in the shell part can be smoothly discharged through the explosion-proof valve under the condition that the battery cell is in thermal runaway, and the safety of the battery cell is ensured.

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 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 usually include a shell, a cover plate, a lower plastic part and a pole group. The shell and the cover plate are enclosed to form a closed space for accommodating the pole group. The lower plastic part is arranged on the side of the cover plate facing the pole group. An explosion-proof valve is usually arranged on the cover plate to discharge the high-pressure gas in the shell. Among them, the battery cell is mainly pressed on the pole group by the lower plastic to achieve the limitation of the battery cell shell on the pole group.

[0004] However, the insulating material used to make the lower plastic is generally made of plastic (such as PP), which has a low melting point. When the battery has thermal runaway, as the temperature inside the battery cell rises sharply, the limiting effect of the lower plastic on the electrode group is easily invalidated due to the melting of the lower plastic, which 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 shell, thereby causing the electrode group to block the explosion-proof valve, thereby affecting the exhaust smoothness of the explosion-proof valve, reducing the exhaust effect of the explosion-proof valve, and reducing the safety performance of the battery cell. Summary of the invention

[0005] The purpose of the present application is to provide a battery cell housing and a battery cell, so as to solve the existing problem in the prior art that the insulating material of the lower plastic is generally made of plastic material with a low melting point. When the battery has thermal runaway, as the temperature inside the battery cell rises sharply, the limiting effect of the lower plastic part on the pole group is very likely to fail due to the melting of the lower plastic part, which makes the pole group very likely 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 pole group to block the explosion-proof valve, thereby affecting the exhaust smoothness of the explosion-proof valve, reducing the exhaust effect of the explosion-proof valve, and reducing the technical problem of the safety performance of the battery cell.

[0006] According to a first aspect of the present application, there is provided a battery cell casing, 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 are enclosed to form a closed space for accommodating an electrode group, and the cover plate is provided with an explosion-proof valve;

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

[0008] The tensile coefficient that the pole group can withstand is defined as δ. When the pole group is pressed against the protruding component, the contact area between the protruding component and the pole 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 pole group in the first direction is F, wherein δ×S>1.5F.

[0009] Preferably, the protrusion assembly comprises a protrusion row formed by a plurality of protrusions arranged at intervals along the circumferential direction of the shell portion, and ends of a plurality of the 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 n, the number of protrusion rows is b, and 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, it further comprises 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 part are covered with each other, at least part of the plastic part extends to the enclosed space.

[0016] Preferably, in the first direction, the distance between one 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 part are covered with each other, the protrusion component 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 beneficial effects of this application are:

[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 pole group, so that the pole group can still remain without obvious movement when the battery cell is impacted by internal gas due to thermal runaway, thereby effectively avoiding the pole group blocking the explosion-proof valve and causing danger, and 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 specifically cited below and described in detail with reference to the attached 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 drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. 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 paying 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 position 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 of the embodiments.

[0029] The components of the embodiments of the present application generally described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the application claimed, but merely represents the 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 the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0032] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0033] Refer to the following Figure 1 and Figure 2 A battery cell casing and a battery cell according to some embodiments of the present application are described.

[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 are enclosed to form a closed space for accommodating the pole group, and the cover plate 1 is provided with an explosion-proof valve 12. The inner side wall of the shell portion 3 close to the cover plate 1 is provided with a protrusion component, and in the first direction F1, the protrusion component is arranged between the cover plate 1 and the pole group. The tensile coefficient that the pole group can withstand is defined as δ, and when the pole group is pressed against the protrusion component, the contact area between the protrusion component and the pole group is S, and when the battery cell is in a thermal runaway state, the pole group is subjected to an impact force F of 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 of 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 pole group, so that the pole group can still remain without obvious movement when the battery cell is impacted by internal gas due to thermal runaway, thereby effectively avoiding the pole 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 may be an example of the first direction F1. For the convenience 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 may be an example of the second direction F2, and F3 shown in the figure may be an example of the third direction F3. Taking the example of the shell structure shown in the figure being applicable to a square shell battery cell as an example, preferably, the first direction F1 may be the length direction of the square shell battery cell, the second direction F2 may be the width direction of the square shell battery cell, and the third direction F3 may be the thickness direction of the square shell 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 abut against the pole group at the same time 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 that 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 rely on the other of the two rows of protrusion rows for limiting.

[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 row group, 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 the 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 in the form of a rectangular parallelepiped as an example, the dimension 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, the number of protrusion rows is b, and 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 position of 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 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 disposed on a 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. Thus, on the one hand, insulation between the explosion-proof cover and the pole group is effectively achieved through the plastic part 2; 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 (eg 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 are covered with each other, in the first direction F1, the protrusion assembly and the plastic part 2 are overlapped, so as to save the 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 may be provided with an avoidance groove 21. When the cover plate 1 and the shell 3 are covered with each other, the protrusion assembly 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 can extend along the first direction F1, and the avoidance groove 21 is opened at one end of the plastic part 2 facing the pole group, so as to facilitate the 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 described in detail herein.

[0054] Preferably, if Figure 1 and Figure 2 As shown, the battery cell may further include a first pole 111 and a second pole 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 disposed on the cover plate 1 .

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

[0058] However, it is not limited thereto, and as not shown in the figure, 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 it. 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 replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell casing, characterized in that: It comprises a shell and a cover plate, wherein the cover plate is arranged on one side of the shell in a first direction, so that the shell and the cover plate are enclosed to form a closed space for accommodating the electrode group, and the cover plate is provided with an explosion-proof valve; The inner side wall of the shell portion close to the cover plate is provided with a protrusion component, and in the first direction, the protrusion component is provided between the cover plate 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 protruding component, the contact area between the protruding component and the pole 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 pole group in the first direction is F, wherein δ×S>1.5F.

2. The battery cell casing according to claim 1, characterized in that: The protrusion assembly includes a protrusion row formed by a plurality of protrusions arranged at intervals along the circumferential direction of the shell portion, and ends of a plurality of the protrusions in the same protrusion row facing the pole group in the first direction are aligned with each other.

3. The battery cell casing 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 casing according to claim 3, characterized in that: 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, 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, characterized in that: 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 the range of 120N to 300N.

6. The battery cell casing according to claim 1, characterized in that: The range of the tensile coefficient δ that the pole group can withstand is 0.8N / mm 2 ~2.5N / mm 2 .

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 part are covered with each other, at least a part of the plastic part extends to the enclosed space.

8. The battery cell casing according to claim 7, characterized in that: In the first direction, the distance between one 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.

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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