Single battery and energy storage device

Abstract

The utility model belongs to the technical field of batteries, and discloses a single battery and an energy storage device. The single battery comprises a shell, battery cover plates, a battery cell group and at least two second anti-explosion valves, the two ends of the shell in the first direction are connected with the battery cover plates in a sealed mode, and the battery cover plates are provided with first anti-explosion valves; the battery cell group is arranged in the shell in an insulating manner and comprises at least two pole groups which are sequentially connected along a first direction; the at least two second anti-explosion valves are symmetrically arranged on the two sides of the shell in the second direction and are arranged corresponding to the joint of the two adjacent pole groups, and the second direction is perpendicular to the first direction; the sum of the pressure relief areas of the at least two second anti-explosion valves is smaller than the sum of the pressure relief areas of the two first anti-explosion valves. According to the single battery, the structural strength and the pressure relief capability of the single battery can be improved while the battery capacity is improved, so that the safety of the single battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a single cell and an energy storage device. Background Art

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields. Currently, the requirements for the use performance and safety of lithium-ion batteries are increasing day by day.

[0003] In order to improve their own capacity and energy density, existing lithium-ion batteries are gradually developing towards long lithium-ion batteries, that is, the length of the battery cells inside the lithium-ion battery is getting larger and larger. This will lead to complex manufacturing processes and low manufacturing precision of the battery cells. Moreover, the proportion of the battery cells inside the existing lithium-ion battery is getting higher and higher, making the capacity and energy density of a single lithium-ion battery larger and larger; but this also causes more and more heat during the operation or charging of a single lithium-ion battery, and the structural strength is getting lower and lower. If a single lithium-ion battery undergoes thermal runaway, the heat dissipation air path is relatively long, and the gas cannot be released quickly, resulting in a rapid increase in the internal pressure of the lithium-ion battery, affecting the safety performance of the battery cells; and the reduction of the structural strength also makes the outer shell of the lithium-ion battery prone to deformation. Especially when the battery cells are in thermal runaway, the deformation degree of the weak parts of the outer shell is large, and the internal battery cells are prone to move and be damaged during its use, which will also affect the safety performance of the battery cells.

[0004] Therefore, there is an urgent need for a new type of single cell to solve the above technical problems. Summary of the Utility Model

[0005] An object of the utility model is to provide a single cell, which can improve the structural strength and pressure relief ability of the single cell while increasing the battery capacity, thereby improving the safety of the single cell.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] The single cell includes:

[0008] An outer shell, with battery covers hermetically connected to both ends of the outer shell along a first direction, and the battery covers are provided with first explosion-proof valves;

[0009] A battery cell group, insulated and arranged inside the outer shell, and the battery cell group includes at least two pole groups connected in sequence along the first direction;

[0010] At least two second explosion-proof valves, symmetrically arranged on both sides of the outer shell along a second direction, and corresponding to the connection parts of two adjacent pole groups, the second direction is perpendicular to the first direction; the sum of the pressure relief areas of two symmetrically arranged second explosion-proof valves is smaller than the sum of the pressure relief areas of the two first explosion-proof valves.

[0011] Optionally, the pressure relief area of the second explosion-proof valve is smaller than that of the first explosion-proof valve.

[0012] Optionally, an exhaust passage is provided between the inner wall of the battery cell group and the outer shell, and one side of the first explosion-proof valve facing the inside of the outer shell and one side of the second explosion-proof valve facing the inside of the outer shell are both arranged in the exhaust passage.

[0013] Optionally, side plates are provided on both sides of the pole group along the third direction, the first direction, the second direction, and the third direction are perpendicular to each other in pairs, and a gap is provided between the circumferential side wall of the side plate and the circumferential side wall of the pole group to form the exhaust passage.

[0014] Optionally, the side plate includes a plurality of first plates and a plurality of second plates, the first plates and the second plates are alternately connected, and the dimension of the second plate along the second direction is smaller than that of the first plate along the second direction, so that the second plate and the air storage area of the exhaust passage are larger.

[0015] Optionally, a support assembly is provided between the two pole groups, and the support assembly is used to support the connection part of two adjacent pole groups.

[0016] Optionally, the support assembly includes two symmetrically arranged support members, a communication cavity is provided on one side of the support member facing the second explosion-proof valve, and the communication cavity communicates with the gap between the outer peripheral wall of the pole group and the inner peripheral wall of the outer shell.

[0017] Optionally, at least one communication hole is provided on one side of the communication cavity away from the second explosion-proof valve, so that the communication cavities of the two support members are communicated.

[0018] Optionally, the sum of the areas of at least one communication hole is not less than the pressure relief area of any one of the two symmetrically arranged second explosion-proof valves.

[0019] Another object of the present invention is to provide an energy storage device, which can improve the structural strength and pressure relief ability of a single battery while increasing the battery capacity, thereby improving the safety of the single battery.

[0020] To achieve this purpose, the present invention adopts the following technical solutions:

[0021] An energy storage device, including the above-mentioned single battery.

[0022] The beneficial effects of the present invention:

[0023] The present utility model provides a single cell and an energy storage device. The battery cell group is divided into a form where multiple pole groups are connected. This not only increases the capacity of the single cell, but also simplifies the manufacturing complexity of the pole group and improves the manufacturing precision of the pole group. On this basis, the single cell not only has a first explosion-proof valve provided on the battery cover plate, but also has at least two second explosion-proof valves provided on the outer shell, such that both ends of each pole group in the first direction have explosion-proof pressure relief structures. Thus, when gas is generated due to thermal runaway of the pole group, the gas can flow through the gap between the outer shell and the battery cell group to the first explosion-proof valve or the second explosion-proof valve for discharge, shortening the travel of the gas exhaust airway, accelerating the gas discharge efficiency, improving the pressure relief and explosion-proof effect of the single cell, and thereby enhancing the safety of the single cell. Moreover, since the wall thickness of the outer shell is generally thinner than that of the battery cover plate, the sum of the pressure relief areas of the two symmetrically arranged second explosion-proof valves is smaller than the sum of the pressure relief areas of the two first explosion-proof valves. This enables most of the gas in the outer shell to be discharged from the first explosion-proof valve and a small part to be discharged from the second explosion-proof valve during thermal runaway, avoiding the problem of excessive pressure relief at the second explosion-proof valve causing deformation and damage to the outer shell, and improving the reliability of the single cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is an exploded view of a single cell from one perspective provided by the specific embodiment of the present utility model;

[0025] Figure 2 is an exploded view of a single cell from another perspective provided by the specific embodiment of the present utility model;

[0026] Figure 3 is a top view of a single cell provided by the specific embodiment of the present utility model;

[0027] Figure 4 is a side view of a single cell provided by the specific embodiment of the present utility model;

[0028] Figure 5 is Figure 2 a partial enlarged view of part A in

[0029] Figure 6 is Figure 3 a cross-sectional view taken along line B-B in

[0030] Figure 7 is an axonometric view of a support assembly provided by the specific embodiment of the present utility model;

[0031] Figure 8 is a side view of a support assembly provided by the specific embodiment of the present utility model;

[0032] Figure 9 is Figure 8 a cross-sectional view taken along line C-C in

[0033] In the figure:

[0034] 10. Outer shell; 20. Battery cover plate; 30. First explosion-proof valve;

[0035] 40. Battery cell group; 41. Electrode group;

[0036] 50. Second explosion-proof valve;

[0037] 60. Side plate; 61. First plate; 62. Second plate;

[0038] 70. Support assembly; 71. Support member; 711. Communication cavity; 712. Communication hole; 713. Exhaust hole; 714. Groove; 715. Rib;

[0039] 80. Support plate; 90. Insulating film; 91. Slit. Detailed implementation manner

[0040] The following further elaborates on the present utility model in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are merely used to explain the present utility model and do not limit the present utility model. Additionally, it should be noted that for the sake of description, only the parts related to the present utility model rather than all the structures are shown in the drawings.

[0041] In the description of the present utility model, unless otherwise clearly specified and defined, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0042] In the present utility model, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above the top of", and "on the top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below the bottom of", and "under the bottom of" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is lower than that of the second feature.

[0043] In the description of this embodiment, the orientation or positional relationships such as "upper", "lower", "left", "right", etc. are based on the orientation or positional relationships shown in the drawings. They are only for the convenience of description and simplifying the operations, 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. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0044] The following refers to Figures 1 to 9 to introduce the single cell and energy storage device provided by the present utility model.

[0045] It should be noted that the first direction is the Figure 1 X direction in Figure 1 the second direction is the Figure 1 Y direction in, and the third direction is the

[0046] Z direction in. The X direction, Y direction, and Z direction are perpendicular to each other in pairs. Figures 1 to 4 Please refer to

[0047] In the single cell of this embodiment, the battery cell group 40 is divided into a form in which a plurality of pole groups 41 are connected. This not only increases the capacity of the single cell, but also simplifies the manufacturing complexity of the pole group 41 and improves the manufacturing precision of the pole group 41. On this basis, in the single cell of this embodiment, not only the first explosion-proof valve 30 is provided on the battery cover plate 20, but also at least two second explosion-proof valves 50 are provided on the outer shell 10, so that explosion-proof pressure relief structures are provided at both ends of each pole group 41 along the first direction. Therefore, when gas is generated due to thermal runaway of the pole group 41, the gas can flow through the gap between the outer shell 10 and the battery cell group 40 to the first explosion-proof valve 30 or the second explosion-proof valve 50 for discharge, shortening the travel of the gas exhaust airway, accelerating the gas discharge efficiency, improving the pressure relief and explosion-proof effect of the single cell, and thus improving the safety of the single cell. And, since the wall thickness of the outer shell 10 is generally thinner than that of the battery cover plate 20, the sum of the pressure relief areas of the two symmetrically arranged second explosion-proof valves 50 is smaller than the sum of the pressure relief areas of the two first explosion-proof valves 30. This can make most of the gas in the outer shell 10 discharge from the first explosion-proof valve 30 and a small part discharge from the second explosion-proof valve 50 during thermal runaway, avoiding the problem of excessive pressure relief at the second explosion-proof valve 50 causing deformation and damage of the outer shell 10, and improving the reliability of the single cell.

[0048] In some embodiments, the pressure relief area of the second explosion-proof valve 50 is smaller than that of the first explosion-proof valve 30, that is, the pressure relief area of each second explosion-proof valve 50 is smaller than that of each first explosion-proof valve 30. This enables most of the gas to be discharged more evenly through the first explosion-proof valve 30 and the other part to be discharged evenly from the second explosion-proof valve 50 during the gas discharge process, avoiding excessive local gas pressure in the single cell that may affect safety and improving the safety of the single cell.

[0049] Optionally, the pressure relief areas of each second explosion-proof valve 50 are the same, and the pressure relief areas of each first explosion-proof valve 30 are the same, so that the pressure relief and exhaust effect of the single cell is more uniform.

[0050] Optionally, the battery cover plate 20 is provided with a first mounting hole for mounting the first explosion-proof valve 30.

[0051] Optionally, at least one second mounting hole is provided on both sides of the outer shell 10 along the second direction for mounting the second explosion-proof valve 50.

[0052] It can be understood that the pressure relief area of the above-mentioned first explosion-proof valve and the pressure relief area of the second explosion-proof valve 50 can also be set by comparing the first mounting hole and the second mounting hole, that is, the area of the second mounting hole is smaller than the area of the first mounting hole.

[0053] In some embodiments, an exhaust passage is provided between the battery cell group 40 and the inner wall of the housing 10. The side facing the inside of the housing 10 of the first explosion-proof valve 30 and the side facing the inside of the housing 10 of the second explosion-proof valve 50 are both disposed in the exhaust passage. The exhaust passage further increases the guiding property of the gas flow inside the single battery, so that when the electrode group 41 is out of control thermally, the gas generated at each position on the outer periphery of the electrode group 41 can be discharged to the first explosion-proof valve 30 and the second explosion-proof valve 50 for rapid pressure relief.

[0054] Please refer to Figure 2 and Figure 5 , specifically, side plates 60 are provided on both sides of the electrode group 41 along the third direction. A gap is provided between the circumferential side wall of the side plate 60 and the circumferential side wall of the electrode group 41 to form an exhaust passage. Such a setting can not only realize the formation of the exhaust passage, but also strengthen the structural strength of the electrode group 41, improve the fixing effect on the electrode group 41, and prevent it from moving and touching the housing 10 and causing damage.

[0055] More specifically, the side plate 60 includes a plurality of first plates 61 and a plurality of second plates 62. The first plates 61 and the second plates 62 are alternately connected. The dimension of the second plate 62 along the second direction is smaller than the dimension of the first plate 61 along the second direction, so that the second plate 62 and the gas storage area of the exhaust passage are larger, so that the exhaust passage has a gas storage part, increasing the volume of the exhaust passage, thereby effectively increasing the gas occupation space inside the housing 10 and delaying the rising speed of the pressure inside the single battery, thus further improving the safety of the single battery.

[0056] Please refer to Figure 2 , Figures 5 to 9 , in some embodiments, a support assembly 70 is provided between the two electrode groups 41. The support assembly 70 is used to support the connection part of the adjacent two electrode groups 41 to improve the connection stability between the adjacent two electrode groups 41.

[0057] Specifically, the series connection of the two electrode groups 41 is realized by welding the electrode tabs between the adjacent two electrode groups 41. The electrode tabs on the side of the electrode group 41 facing the other electrode group 41 extend along the first direction. The support assembly 70 supports the connection part of the electrode tabs of the two electrode groups 41, so that when the electrode tabs of the two electrode groups 41 are connected, they are connected after being inserted flat and overlapping, so as to avoid the bending and fixing of the electrode tabs, shorten the length of the electrode tabs, improve the space utilization rate, simplify the processing technology, and at the same time reduce the internal resistance.

[0058] In some embodiments, the support assembly 70 includes two symmetrically arranged support members 71. By dividing the support assembly 70 into two support members 71, it is not only convenient for the installation of the support assembly 70, but also can support the connection between two adjacent pole groups 41. Specifically, the support member 71 is provided with a groove 714, and the grooves 714 of the two support members 71 are buckled to form a support cavity, and the connection of the tabs of two adjacent pole groups 41 is arranged in the support cavity. The arrangement of the groove 714 provides a receiving position for the tabs and also supports the tabs, improving the connection reliability of the tab connection of the two pole groups 41.

[0059] Optionally, the support member 71 has a square structure, so that the surface of the support member 71 in contact with the pole group 41 is a flat surface, thus better playing the role of fixing and supporting.

[0060] Optionally, the two support members 71 can be symmetrically connected along the first direction or symmetrically connected along the second direction, both of which can realize the forming and assembling of the support assembly 70 to fix the tab connection of the pole group 41.

[0061] In some embodiments, the support assembly 70 includes two symmetrically arranged support members 71. A communication cavity 711 is formed on the side of the support member 71 facing the second explosion-proof valve 50, and the communication cavity 711 communicates with the gap between the outer peripheral wall of the pole group 41 and the inner peripheral wall of the housing 10, so that even if there is a support assembly 70 between adjacent pole groups 41, it does not affect the discharge of the gas around each pole group 41 in the housing 10 by the second explosion-proof valve 50. And the two support members 71 are symmetrically arranged to ensure that the pressure relief and explosion-proof effects can be achieved on both sides of the single battery along the second direction, avoiding excessive pressure on the other side caused by only setting the second explosion-proof valve 50 on one side, and improving the safety of the single battery.

[0062] Specifically, exhaust holes 713 are arranged on both sides of the communication cavity 711 along the third direction to communicate the gap between the battery cell group 40 and the housing 10 with the second explosion-proof valve 50, so as to realize the communication between the communication cavity 711 and the exhaust passage.

[0063] In some alternative embodiments, at least one communication hole 712 is formed on the side of the communication cavity 711 away from the second explosion-proof valve 50 to connect the communication cavities 711 of the two support members 71, so that the gas on both sides of the single battery is connected, thus further avoiding the safety problems caused by uneven pressure on both sides of the single battery along the second direction during thermal runaway of the single battery, and further improving the safety of the single battery.

[0064] Optionally, the sum of the areas of at least one communication hole 712 is not less than the pressure relief area of any one of at least two second explosion-proof valves 50. This setting prevents all the gas in the communication cavity 711 from flowing out through the second explosion-proof valve 50 when the pressure relief area of the second explosion-proof valve 50 is larger, and instead, the gas will not flow through the communication hole 712 into the communication cavity 711 of another support member 71, thus preventing the pressures on both sides of the housing 10 from being equalized.

[0065] In some embodiments, ribs 715 are further provided on both sides of the support member 71 along the third direction. The ribs 715 of the two support members 71 and the body of the support member 71 enclose a channel, which is connected to the exhaust channel. The ribs 715 prevent gas leakage, allowing the gas in the exhaust channel of the electrode group 41 to enter the channel and pass through the exhaust holes 713 into the communication cavity 711, and then be discharged from the communication cavity 711 through the second explosion-proof valve 50.

[0066] Please refer to Figure 1 and Figure 2 , in some embodiments, support plates 80 are further provided at both ends of the battery cell group 40 along the first direction to provide support for the battery cell group 40. When the battery cell group 40 is installed in the housing 10, force can be applied stably and evenly through the support plates 80, thereby realizing the installation of the battery cell group 40.

[0067] It can be understood that the above-mentioned support assembly 70, support plates 80, and side plates 60 are all made of insulating materials to prevent the electrode group 41 from short-circuiting and improve the safety of the battery cell group 40.

[0068] In some embodiments, at least one of the two battery covers 20 is structurally simplified, that is, only the cover body, the pole post protrusion on the cover body, and the first explosion-proof valve 30 are retained, without other structures such as upper plastic and lower plastic. This not only simplifies the structure but also reduces costs and improves space utilization.

[0069] In some embodiments, the single battery further includes an insulating film 90, which is wrapped around the outer periphery of the battery cell group 40 to insulate the battery cell group 40 from the housing 10.

[0070] Optionally, a slit 91 is provided in the insulating film 90 corresponding to the second explosion-proof valve 50 to make this part vulnerable. When the electrode group 41 experiences thermal runaway, the slit 91 in the insulating film 90 can be broken through to discharge the gas.

[0071] This embodiment also provides an energy storage device, which includes the single battery described in any of the above solutions. The energy storage device is a structure such as a battery module or a battery pack that loads the single battery and realizes electricity storage and external power supply. By adopting the above single battery, the energy storage device not only improves the capacity and energy density but also enhances the structural strength and safety to a certain extent.

[0072] Obviously, the above embodiments of the present utility model are merely examples for clearly illustrating the present utility model, rather than limitations on the implementation manners of the present utility model. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present utility model. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the claims of the present utility model.

Claims

1. A single cell, characterized in that, Comprising: A housing, with battery covers hermetically connected to both ends of the housing along a first direction, and the battery covers are provided with first explosion-proof valves; A battery cell group, insulated and disposed within the housing, and the battery cell group includes at least two pole groups sequentially connected along the first direction; At least two second explosion-proof valves, symmetrically disposed on both sides of the housing along a second direction, and corresponding to the connection positions of two adjacent pole groups, the second direction being perpendicular to the first direction; the sum of the pressure relief areas of two mutually symmetric second explosion-proof valves is less than the sum of the pressure relief areas of the two first explosion-proof valves.

2. The single cell according to claim 1, characterized in that, The pressure relief area of the second explosion-proof valve is less than the pressure relief area of the first explosion-proof valve.

3. The single cell according to claim 1, characterized in that, An exhaust passage is provided between the battery cell group and the inner wall of the housing, and the side facing the inside of the housing of the first explosion-proof valve and the side facing the inside of the housing of the second explosion-proof valve are both disposed within the exhaust passage.

4. The single cell according to claim 3, characterized in that, Side plates are provided on both sides of the pole group along a third direction, the first direction, the second direction, and the third direction are mutually perpendicular to each other, and a gap is provided between the circumferential side wall of the side plate and the circumferential side wall of the pole group to form the exhaust passage.

5. The single cell according to claim 4, characterized in that, The side plate includes a plurality of first plates and a plurality of second plates, the first plates and the second plates are alternately connected, and the dimension of the second plate along the second direction is smaller than the dimension of the first plate along the second direction, so that the second plate and the gas storage area of the exhaust passage are larger.

6. The single cell according to any one of claims 1-5, characterized in that, A support assembly is provided between the two pole groups, and the support assembly is used to support the connection position of two adjacent pole groups.

7. The single cell according to claim 6, characterized in that, The support assembly includes two symmetrically disposed support members, and a communication cavity is provided on the side of the support member facing the second explosion-proof valve, and the communication cavity communicates with the gap between the outer peripheral wall of the pole group and the inner peripheral wall of the housing.

8. The single cell according to claim 7, characterized in that, At least one communication hole is provided on the side of the communication cavity away from the second explosion-proof valve, so that the communication cavities of the two support members are communicated.

9. The single cell according to claim 8, characterized in that, The sum of the areas of at least one communication hole is not less than the pressure relief area of any one of the two mutually symmetric second explosion-proof valves.

10. Energy storage device, characterized in that, Including a single battery according to any one of claims 1-9.

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