Battery pole group fixing structure and battery

Abstract

The utility model relates to the technical field of batteries, and discloses a battery pole group fixing structure and a battery, the battery pole group fixing structure comprises a shell, the inner side peripheral wall of the shell is enclosed to form a containing cavity, and the containing cavity is suitable for containing a pole group; an anti-explosion valve is arranged on the cover plate, and the anti-explosion valve and the pole group are arranged in a spaced mode in the first direction; the end plate is arranged on one side, facing the cover plate in the first direction, of the pole group; and the wrapping body wraps the end, close to the anti-explosion valve, of the end plate in the second direction, and the wrapping body is suitable for delaying and / or isolating heat transfer between the end plate and the pole group when the battery cell triggers thermal runaway. According to the battery pole group fixing structure provided by the utility model, the wrapping body can independently support the pole group and / or the wrapping body and the wrapped part of the end plate can simultaneously support the pole group, so that the pole group is prevented from moving towards the end plate along the first direction, the pole group is prevented from shielding the anti-explosion valve, the temperature rise speed of the battery cell due to thermal runaway is effectively delayed, and the safety of the battery cell is improved. The peak temperature of the battery cell is reduced, and the battery cell thermal runaway test passing rate is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery pole group fixing structure and a battery. Background Art

[0002] Lithium-ion batteries have been widely used in energy storage systems such as hydropower, thermal power, wind power, as well as in power, aerospace and other fields due to their high energy density, low self-discharge, no memory effect, wide operating range, fast charge and discharge, long service life and no environmental pollution.

[0003] The existing lithium-ion battery structure usually includes components such as a cover plate, a shell, an end plate, a side plate, a bare cell insulating sheet, an electrode group and an electrolyte, among which the cover plate is integrated with a pole, an explosion-proof valve and a liquid injection hole, etc.; the side plate, the bare cell insulating sheet, the end plate and the lower plastic constitute the insulating protection structure of the electrode group, so as to prevent the electrode group from overlapping with the shell or the cover plate and causing short circuits and other problems during normal use of the battery cell; the cover plate and the shell are fixed by welding to form a closed space with a certain mechanical strength to protect the electrode group; the main function of the explosion-proof valve integrated on the cover plate is: when the battery cell is short-circuited and out of control due to external damage, improper use, etc., the high-temperature and high-pressure gas inside the battery cell is discharged in a timely and directional manner to prevent the battery cell from exploding at will, thereby avoiding unpredictable personal safety threats and property losses to users.

[0004] However, in the existing lithium-ion battery structure, when the battery cell triggers thermal runaway, after the end plate and the lower plastic are melted, the electrode group is likely to move toward the explosion-proof valve and block the explosion-proof valve, affecting the exhaust and heat dissipation of the battery and reducing the safety performance of the battery. Utility Model Content

[0005] In view of this, the utility model provides a battery pole group fixing structure and a battery to solve the problem that after the end plate and the lower plastic of the existing lithium-ion battery structure are melted, the pole group is easy to move toward the explosion-proof valve and block the explosion-proof valve, affecting the exhaust and heat dissipation of the battery.

[0006] In a first aspect, the utility model provides a battery electrode group fixing structure, comprising:

[0007] The housing has an inner peripheral wall enclosing a receiving cavity, and the receiving cavity is suitable for receiving the pole group;

[0008] A cover plate, which is arranged on one side of the housing along the first direction, and an explosion-proof valve is arranged on the cover plate, and the explosion-proof valve is spaced apart from the electrode group along the first direction;

[0009] An end plate, arranged on one side of the electrode group facing the cover plate along the first direction;

[0010] The encapsulation body is encapsulated on one end of the end plate close to the explosion-proof valve along the second direction, and the encapsulation body is suitable for delaying and / or isolating heat transfer between the end plate and the pole group when the battery cell triggers thermal runaway.

[0011] The battery pole group fixing structure provided by the utility model has a coating body arranged at one end of the end plate close to the explosion-proof valve along the second direction, and the coating body can withstand the high temperature in the battery cell during thermal runaway, so that the coated part of the end plate is thermally isolated from the pole group through the coating body; when thermal runaway occurs in the battery cell, the coating body can not only delay and / or isolate the heat transfer between the coated part of the end plate and the pole group, but also the coating body can support the pole group alone and / or the coating body and the coated part of the end plate (the unmelted part of the end plate during thermal runaway) can support the pole group at the same time, thereby preventing the pole group from moving toward the end plate along the first direction, avoiding the pole group from blocking the explosion-proof valve, effectively delaying the speed of heating of the battery cell due to thermal runaway, reducing the peak temperature of the battery cell, greatly improving the pass rate of thermal runaway test of the battery cell, and thus improving the safety performance of the battery cell and even the entire battery pack.

[0012] In an optional embodiment, the coating body includes a bottom plate and a side plate extending from the bottom plate along a first direction toward a direction away from the bottom plate; the bottom plate is attached to a side of the end plate along the first direction toward the pole group, and the side of the bottom plate along the first direction away from the end plate is suitable for abutting against the pole group; the side plate is attached to the side wall of the end plate, and the side of the side plate along the first direction away from the bottom plate is suitable for abutting against the cover plate.

[0013] By such an arrangement, the side of the bottom plate away from the end plate along the first direction abuts against the pole group, thereby delaying and / or isolating the heat transfer between the side of the end plate toward the pole group along the first direction and the pole group; the side plate is attached to the side wall of the end plate, thereby delaying and / or isolating the heat transfer between the side wall of the end plate and the pole group, and the side of the side plate away from the bottom plate along the first direction abuts against the cover plate, thereby preventing the pole group from moving toward the end plate along the first direction when the battery cell has thermal runaway, thereby avoiding the pole group from blocking the explosion-proof valve.

[0014] In an optional embodiment, the total width of the enclosure along the third direction is L, and L satisfies 0.5·P≤L≤0.95·W, wherein P is the total width of the end plate along the third direction, and W is the width of the accommodating cavity along the third direction.

[0015] This arrangement can, on the one hand, prevent the support of the coating from becoming unstable when thermal runaway occurs in the battery cell, thereby ensuring that the coating stably supports the electrode group; on the other hand, it can prevent interference between the coating and the shell when inserting the coating, thereby facilitating assembly.

[0016] In an optional embodiment, the total height of the enclosure along the first direction is H, and H satisfies 0.5·E≤H≤2·E, wherein E is the total height of the end plate along the first direction.

[0017] Through such an arrangement, on the one hand, sufficient exhaust channels can be ensured between the pole group and the explosion-proof valve when thermal runaway occurs in the battery cell, so that exhaust and heat can be dissipated in time when thermal runaway occurs in the battery cell, and on the other hand, the capacity of the battery cell can be guaranteed.

[0018] In an optional embodiment, the thickness of the bottom plate is M, and M satisfies 0.5 mm ≤ M ≤ 10 mm.

[0019] Such an arrangement is beneficial for processing on the one hand, and on the other hand, the strength of the bottom plate is ensured. On the other hand, when the battery cell triggers thermal runaway, the heat transfer between the end plate and the pole group can be effectively delayed and / or isolated, while the volume energy density of the battery cell can be ensured, which is beneficial for lightweighting the battery cell.

[0020] In an optional embodiment, the thickness of the side panel is T, and T satisfies 0.5·M≤T≤2·M.

[0021] Such a setting is beneficial for processing on the one hand, and on the other hand, it ensures the supporting stiffness of the side panels, thereby providing stable support for the pole group when the battery cell triggers thermal runaway, while ensuring the mass energy density of the battery cell, which is beneficial for lightweighting the battery cell.

[0022] In an optional embodiment, a through groove is provided on one side of the end plate close to the pole group along the first direction; one of the side plates of the covering body along the third direction is inserted into the through groove;

[0023] An avoidance groove is formed between two adjacent side plates on both sides of the side plate in the third direction; and the end plates are inserted into the avoidance groove along the side walls on both sides of the third direction.

[0024] Through such an arrangement, not only can the covering body be limited, which is convenient for the covering body and the end plate to be inserted into the shell together, but also the side panels are arranged opposite to each other in the second direction and the third direction, which is beneficial to improve the overall support strength of the covering body, thereby stably supporting the electrode group when the battery cell triggers thermal runaway.

[0025] In an optional embodiment, a reinforcing rib is provided between two adjacent side panels.

[0026] By such arrangement, the overall support strength of the coating is further improved, thereby providing stable support for the electrode group when the battery cell triggers thermal runaway.

[0027] In an optional embodiment, the encapsulation body is made of an insulating, high-temperature and electrolyte-resistant material.

[0028] Through such a setting, the electrode group can be well protected during the battery cell manufacturing process and normal use to avoid abnormal overlap and short circuit inside the battery cell, and the electrode group can be stably and effectively supported when the battery cell triggers thermal runaway.

[0029] In a second aspect, the utility model further provides a battery, comprising: a battery body, and the battery pole group fixing structure as described above.

[0030] The battery of the second aspect includes the battery pole group fixing structure of the first aspect, and thus the battery of the second aspect includes all the beneficial effects of the battery pole group fixing structure of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the utility model 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 utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A schematic diagram of the three-dimensional structure of a battery pole group fixing structure according to an embodiment of the utility model;

[0033] Figure 2 for Figure 1 Schematic diagram of the exploded structure of the battery pole group fixing structure behind the hidden shell and pole group;

[0034] Figure 3 A schematic diagram of the three-dimensional structure of a package of a battery electrode group fixing structure according to an embodiment of the utility model;

[0035] Figure 4 for Figure 1 A schematic diagram of the structure of the accommodating cavity of the shell;

[0036] Figure 5 This is a schematic diagram of the connection between the encapsulation body and the end plate of a battery pole group fixing structure according to an embodiment of the utility model;

[0037] Figure 6 for Figure 1 A schematic diagram of a top view of a battery electrode group fixing structure shown;

[0038] Figure 7 for Figure 6 Schematic diagram of the cross-sectional structure of the AA section;

[0039] Figure 8 for Figure 7 A local enlarged schematic diagram of the K in the middle;

[0040] Fig. 9 It is a schematic diagram of the three-dimensional structure of a covering body of a battery pole group fixing structure according to an embodiment of the utility model.

[0041] Description of reference numerals:

[0042] 10. housing; 101. accommodating chamber;

[0043] 20. Pole group;

[0044] 30. Cover plate; 31. Explosion-proof valve;

[0045] 40, end plate; 401, through slot;

[0046] 50. Envelope; 501. Avoidance groove; 51. Bottom plate; 52. Side plate; 53. Reinforcement rib. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0048] In the related technology, the electrode group insulation protection structure inside the battery cell is made of plastic materials such as PP, which can well protect the electrode group during the battery cell manufacturing process and normal use to avoid abnormal connection and short circuit inside the battery cell. However, when the battery cell has thermal runaway, the internal temperature can reach above 600°C in a short period of time, and the internal plastic materials such as the side panels, bare battery cell insulation sheets, end panels, and lower plastic will quickly melt and fail. At this time, there is only the electrode group inside the shell. Under the action of the internal high-temperature and high-pressure gas, the electrode group loses balance. Because the pressure at the explosion-proof valve of the positive cover is relatively low, the electrode group can easily move toward the explosion-proof valve, thereby blocking the explosion-proof valve, causing the battery to fail to release pressure in time and catch fire and explode.

[0049] Combine the following Figures 1 to 9 , describing an embodiment of the utility model.

[0050] According to an embodiment of the present utility model, on the one hand, a battery pole group fixing structure is provided, comprising:

[0051] The housing 10 has an inner peripheral wall enclosing a receiving cavity 101, and the receiving cavity 101 is suitable for receiving the pole group 20;

[0052] A cover plate 30 is disposed on one side of the housing 10 along the first direction. An explosion-proof valve 31 is disposed on the cover plate 30. The explosion-proof valve 31 is spaced apart from the electrode group 20 along the first direction.

[0053] The end plate 40 is disposed on one side of the electrode group 20 facing the cover plate 30 along the first direction;

[0054] The covering body 50 covers one end of the end plate 40 close to the explosion-proof valve 31 along the second direction. The covering body 50 is suitable for delaying and / or isolating heat transfer between the end plate 40 and the electrode group 20 when the battery cell triggers thermal runaway.

[0055] Furthermore, the covering body 50 is bonded to the end plate 40 .

[0056] The battery pole group fixing structure provided in the present embodiment is provided with a coating 50 at one end of the end plate 40 close to the explosion-proof valve 31 along the second direction. The coating 50 can withstand the high temperature in the battery cell during thermal runaway, so that the coated part of the end plate 40 is thermally isolated from the pole group 20 through the coating 50; when thermal runaway occurs in the battery cell, the coating 50 can not only delay and / or isolate the heat transfer between the coated part of the end plate 40 and the pole group 20, but also the coating 50 can support the pole group 20 alone and / or the coating 50 and the coated part of the end plate 40 (the part of the end plate 40 that has not melted temporarily during thermal runaway) can support the pole group 20 at the same time, thereby preventing the pole group 20 from moving toward the end plate 40 along the first direction, avoiding the pole group 20 from blocking the explosion-proof valve 31, effectively delaying the speed of heating of the battery cell due to thermal runaway, reducing the peak temperature of the battery cell, greatly improving the pass rate of thermal runaway test of the battery cell, and thus improving the safety performance of the battery cell and even the entire battery pack.

[0057] In some embodiments, see Figure 3 As shown, the covering body 50 includes a bottom plate 51 and a side plate 52 extending from the bottom plate 51 along a first direction away from the bottom plate 51; Figure 1 and Figure 2 As shown, the bottom plate 51 is attached to the side of the end plate 40 facing the pole group 20 along the first direction, and the side of the bottom plate 51 away from the end plate 40 along the first direction is suitable for abutting against the pole group 20, thereby delaying and / or isolating the heat transfer between the side of the end plate 40 facing the pole group 20 along the first direction and the pole group 20; the side plate 52 is attached to the side wall of the end plate 40, thereby delaying and / or isolating the heat transfer between the side wall of the end plate 40 and the pole group 20, and the side of the side plate 52 away from the bottom plate 51 along the first direction is suitable for abutting against the cover plate 30, thereby preventing the pole group 20 from moving toward the end plate 40 along the first direction when the battery cell is thermally runaway, thereby avoiding the pole group 20 from blocking the explosion-proof valve 31.

[0058] In some embodiments, see Figure 5 As shown, the total width of the covering body 50 along the third direction is L. If the total width of the covering body 50 along the third direction is too small, the covering body 50 is easy to support instability when the battery cell has thermal runaway, and it is difficult to stably support the electrode group 20. Therefore, the total width L of the covering body 50 along the third direction needs to satisfy L≥0.5·P, wherein, still refer to Figure 5As shown, P is the total width of the end plate 40 along the third direction; if the total width of the covering body 50 along the third direction is too large, the covering body 50 is easy to interfere with the shell 10 when inserted into the shell, which is not conducive to assembly. Therefore, the total width L of the covering body 50 along the third direction must also satisfy L≤0.95·W, where, see Figure 4 As shown, W is the width of the accommodating cavity 101 along the third direction. In this embodiment, the total width L of the encapsulation body 50 along the third direction satisfies 0.5·P≤L≤0.95·W, where P is the total width of the end plate 40 along the third direction, and W is the width of the accommodating cavity 101 along the third direction. On the one hand, it can prevent the encapsulation body 50 from supporting instability when thermal runaway occurs in the battery cell, ensuring that the encapsulation body 50 stably supports the electrode group 20. On the other hand, it can prevent the encapsulation body 50 from interfering with the shell 10 when the battery cell is inserted into the shell, which is convenient for assembly.

[0059] In some embodiments, see Figure 5 As shown, the total height of the covering body 50 along the first direction is H. The total height of the covering body 50 along the first direction cannot be too small, otherwise it is easy to cause the exhaust channel between the pole group 20 and the explosion-proof valve 31 to be too small when the battery cell has thermal runaway, affecting the exhaust and heat dissipation of the battery cell when the battery cell has thermal runaway. Therefore, the total height H of the covering body 50 along the first direction needs to satisfy H≥0.5·E, wherein, still refer to Figure 5 As shown, E is the total height of the end plate 40 along the first direction; since the internal space of the accommodating cavity 101 of the shell 10 is limited, the total height of the covering body 50 along the first direction cannot be too large, otherwise it is easy to affect the size of the pole group 20, resulting in a reduction in the capacity of the battery cell. Therefore, the total height H of the covering body 50 along the first direction must also satisfy H≤2·E. In this embodiment, the total height H of the covering body 50 along the first direction satisfies 0.5·E≤H≤2·E, where E is the total height of the end plate 40 along the first direction. On the one hand, it can ensure that there is enough exhaust channel between the pole group 20 and the explosion-proof valve 31 when the battery cell has thermal runaway, so that the battery cell can be exhausted and dissipated in time when the battery cell has thermal runaway, and on the other hand, it can ensure the capacity of the battery cell.

[0060] In some embodiments, see Figure 8As shown, the thickness of the bottom plate 51 is M. If the thickness of the bottom plate 51 is too small, on the one hand, it cannot be processed, and on the other hand, it is easy to cause insufficient strength of the bottom plate 51. On the other hand, it is difficult to effectively delay and / or isolate the heat transfer between the end plate 40 and the electrode group 20 when the battery cell triggers thermal runaway. Therefore, the thickness M of the bottom plate 51 needs to satisfy M≥0.5mm; since the internal space of the accommodating cavity 101 of the shell 10 is limited, if the thickness of the bottom plate 51 is too large, it not only increases the weight of the battery cell, but also easily affects the size of the electrode group 20, resulting in a decrease in the volume energy density of the battery cell. Therefore, the thickness M of the bottom plate 51 needs to satisfy M≤10mm. In this embodiment, the thickness M of the bottom plate 51 satisfies 0.5mm≤M≤10mm, which is beneficial for processing on the one hand, and ensures the strength of the bottom plate 51 on the other hand. On the other hand, when the battery cell triggers thermal runaway, it can effectively delay and / or isolate the heat transfer between the end plate 40 and the pole group 20, while ensuring the volume energy density of the battery cell, which is beneficial to lightweighting of the battery cell.

[0061] In some embodiments, see Figure 8 As shown, the thickness of the side plate 52 is T. If the thickness of the side plate 52 is too small, it cannot be processed on the one hand, and on the other hand, it is easy to cause the support stiffness of the side plate 52 to be insufficient, and it is difficult to stably support the pole group 20 when the battery cell triggers thermal runaway. Therefore, the thickness T of the side plate 52 needs to satisfy T≥0.5·M, where M is the thickness of the bottom plate 51; if the thickness of the side plate 52 is too large, it is easy to increase the weight of the battery cell, resulting in a decrease in the mass energy density of the battery cell. Therefore, the thickness T of the side plate 52 needs to satisfy T≤2·M. In this embodiment, the thickness T of the side plate 52 satisfies 0.5·M≤T≤2·M, which is conducive to processing on the one hand, and ensures the support stiffness of the side plate 52 on the other hand, so that the pole group 20 is stably supported when the battery cell triggers thermal runaway, and the mass energy density of the battery cell can be ensured at the same time, which is conducive to lightweighting of the battery cell.

[0062] In some embodiments, see Figure 5 As shown, a through groove 401 is provided on one side of the end plate 40 close to the pole group 20 along the first direction; one of the side plates 52 of the encapsulation body 50 along the third direction is inserted into the through groove 401; an avoidance groove 501 is formed between the two adjacent side plates 52 on both sides of the side plate 52 in the third direction; the side walls of the end plate 40 on both sides along the third direction are inserted into the avoidance groove 501, which can not only limit the encapsulation body 50 to facilitate the encapsulation body 50 and the end plate 40 to enter the shell together, but also the side plates 52 are arranged opposite to each other in the second direction and the third direction, which is beneficial to improve the overall support strength of the encapsulation body 50, thereby stably supporting the pole group 20 when the battery cell triggers thermal runaway.

[0063] In some embodiments, see Fig. 9As shown, a reinforcing rib 53 is provided between two adjacent side plates 52, so as to further improve the overall supporting strength of the encapsulation body 50, thereby stably supporting the electrode group 20 when the battery cell triggers thermal runaway.

[0064] In some embodiments, the coating 50 is made of an insulating, high-temperature, and electrolyte-resistant material. For example, the coating 50 can be made of a hard ceramic silicone rubber material or a ceramic material. By using an insulating, high-temperature, and electrolyte-resistant material, the coating 50 can not only protect the electrode group 20 well during the battery cell manufacturing process and normal use, avoiding abnormal bridging and short circuits inside the battery cell, but also provide stable and effective support for the electrode group 20 when the battery cell triggers thermal runaway.

[0065] According to an embodiment of the present invention, on the other hand, a battery is provided, comprising: a battery body, and the battery pole group fixing structure as described above.

[0066] Since the battery in the present solution includes the above-mentioned battery pole group fixing structure, the battery in the present solution includes all the beneficial effects of the above-mentioned battery pole group fixing structure.

[0067] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery pole group fixing structure, It is characterized in that include: A shell, the inner peripheral wall of which encloses a receiving cavity, and the receiving cavity is suitable for receiving the pole group; A cover plate, which is disposed on one side of the housing along the first direction, and an explosion-proof valve is disposed on the cover plate, and the explosion-proof valve is spaced apart from the pole group along the first direction; An end plate, arranged on a side of the pole group facing the cover plate along the first direction; The encapsulation body is encapsulated on one end of the end plate close to the explosion-proof valve along the second direction, and the encapsulation body is suitable for delaying and / or isolating heat transfer between the end plate and the pole group when the battery cell triggers thermal runaway.

2. The battery pole group fixing structure according to claim 1, It is characterized in that The encapsulation body includes a bottom plate and a side plate extending from the bottom plate along a first direction toward a direction away from the bottom plate; the bottom plate is attached to a side of the end plate along the first direction toward the pole group, and a side of the bottom plate along the first direction away from the end plate is suitable for abutting against the pole group; the side plate is attached to a side wall of the end plate, and a side of the side plate along the first direction away from the bottom plate is suitable for abutting against the cover plate.

3. The battery pole group fixing structure according to claim 1, It is characterized in that The total width of the enclosure along the third direction is L, and L satisfies 0.5·P≤L≤0.95·W, wherein P is the total width of the end plate along the third direction, and W is the width of the accommodating cavity along the third direction.

4. The battery pole group fixing structure according to claim 1, It is characterized in that The total height of the cladding body along the first direction is H, and H satisfies 0.5·E≤H≤2·E, wherein E is the total height of the end plate along the first direction.

5. The battery pole group fixing structure according to claim 2, It is characterized in that The thickness of the bottom plate is M, and M satisfies 0.5 mm ≤ M ≤ 10 mm.

6. The battery pole group fixing structure according to claim 5, It is characterized in that The thickness of the side plate is T, and T satisfies 0.5·M≤T≤2·M.

7. The battery pole group fixing structure according to claim 2, It is characterized in that A through groove is formed on one side of the end plate close to the pole group along the first direction; one of the side plates of the covering body along the third direction is inserted into the through groove; An avoidance groove is formed between two adjacent side panels on both sides of the side panel in the third direction; and the end panel is inserted into the avoidance groove along the side walls on both sides of the third direction.

8. The battery pole group fixing structure according to claim 2, It is characterized in that A reinforcing rib is arranged between two adjacent side panels.

9. The battery pole group fixing structure according to any one of claims 1 to 8, It is characterized in that The coating body is made of insulating, high-temperature and electrolyte-resistant material.

10. A battery, It is characterized in that include: A battery body, and a battery pole group fixing structure as described in any one of claims 1 to 9.

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