Battery monomer and battery pack

Abstract

The utility model relates to the technical field of new energy batteries, and discloses a single battery and a battery pack, the single battery has a first direction and a second direction which are intersected, the single battery comprises a shell, the shell comprises a side plate and a bottom plate, the side plate and the bottom plate enclose an accommodating cavity, the bottom plate is provided with a pressure relief hole, the pressure relief hole penetrates through the bottom plate along the first direction, and the first direction is perpendicular to the second direction; the bottom plate is further provided with a weak part, and the weak part and the pressure relief hole are arranged at intervals in the second direction; the anti-explosion valve is fixedly connected with the bottom plate, and the anti-explosion valve seals the pressure relief hole; the bottom plate is further provided with a first flow channel, a second flow channel and a third flow channel, the first flow channel communicates with the containing cavity and the weak part, the second flow channel communicates with the containing cavity and the pressure relief hole, and the third flow channel communicates with the weak part and the pressure relief hole. When the gas in the accommodating cavity is accumulated in a short time and cannot be discharged through the anti-explosion valve, the weak part can be broken through by the high-temperature and high-pressure gas, and the high-temperature and high-pressure gas can be rapidly discharged through the anti-explosion valve and the weak part at the same time, so that the explosion of the single battery is avoided, and the safety of the single battery is improved.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, and in particular to a battery cell and battery pack. Background Technology

[0002] When a lithium-ion battery experiences thermal runaway, it is necessary to promptly release the high-temperature, high-pressure gases generated inside. Therefore, lithium-ion batteries are typically equipped with explosion-proof valves to achieve rapid pressure relief. The stability of the venting during thermal runaway is a key characteristic of cell safety.

[0003] High-capacity lithium-ion batteries produce a lot of gas during thermal runaway. A large amount of gas accumulates near the explosion-proof valve of the lithium-ion battery, which cannot be vented in time. If the high-temperature and high-pressure gas cannot be released in time, the lithium-ion battery is at risk of explosion, which seriously affects the safety of the battery. Utility Model Content

[0004] The purpose of this invention is to provide a battery cell to solve the problem that lithium-ion batteries in the prior art cannot release gas in time, which affects safety; this invention also provides a battery pack using this battery cell.

[0005] To achieve the above objectives, this utility model provides a battery cell having intersecting first and second directions, the battery cell comprising:

[0006] The housing includes a side plate and a bottom plate, the side plate and the bottom plate forming a receiving cavity, the bottom plate is provided with a pressure relief hole, the pressure relief hole penetrates the bottom plate along a first direction, and the bottom plate is also provided with a weak part on the side facing the receiving cavity, and along a second direction, the weak part and the pressure relief hole are spaced apart;

[0007] An explosion-proof valve is fixedly connected to the base plate and seals the pressure relief hole.

[0008] The bottom plate is further provided with a first flow channel, a second flow channel and a third flow channel on the side facing the receiving cavity. The first flow channel connects the receiving cavity and the weak part, the second flow channel connects the receiving cavity and the pressure relief hole, and the third flow channel connects the weak part and the pressure relief hole.

[0009] In some embodiments, the base plate includes a first plate and a second plate connected to each other along a second direction. Along the first direction, the first plate has a size of L1 mm and the second plate has a size of L2 mm, where L1 > L2, so that a pressure relief groove is formed at the second plate of the base plate, and the pressure relief groove forms the weak part.

[0010] In some embodiments, the base plate is provided with a groove, the groove forming the weak part, and the outline shape of the groove in the cross section perpendicular to the first direction is at least one of polygonal, annular, and racetrack-shaped.

[0011] In some embodiments, the base plate is further provided with grooves along the first direction, the grooves are provided on the side of the base plate away from the weak part, and the weak part is provided opposite to the grooves along the first direction.

[0012] In some embodiments, the notch includes one of a semi-circle, an I-shape, or a wave shape.

[0013] In some embodiments, the battery cell further includes a protective film attached to the base plate, wherein the orthographic projection of the protective film onto the base plate along the first direction covers the groove.

[0014] In some embodiments, the protective film is further provided with air vents that penetrate the protective film along the first direction and partially overlap with the grooves along the first direction.

[0015] In some embodiments, the battery cell further includes a bottom support plate disposed in the receiving cavity. Along the second direction, the bottom support plate has a first gap with the side plate. Along the third direction, the bottom support plate has a second gap with the side plate. The first flow channel communicates with the first gap and the second gap, respectively. The second flow channel communicates with the second gap. The first direction, the second direction, and the third direction intersect each other.

[0016] In some embodiments, the third flow channel extends along the second direction, the second flow channel extends along the third direction, and there are multiple first flow channels, with some of the first flow channels extending along the second direction and some of the first flow channels extending along the third direction.

[0017] This utility model also provides a battery pack, including the battery cells described in any of the above technical solutions.

[0018] Compared with the prior art, the beneficial effects of this embodiment of the battery cell and battery pack are as follows: a weak part is provided on the bottom plate of the casing, which is spaced apart from the pressure relief hole along the second direction. When the battery cell experiences thermal runaway, high-temperature and high-pressure gas will enter the pressure relief hole through the first flow channel, the weak part, the second flow channel, and the third flow channel, first rupturing the explosion-proof valve on the pressure relief hole to release gas; when the gas in the containment cavity accumulates in a short time and cannot be discharged through the explosion-proof valve, the gas pressure entering the weak part through the first flow channel increases, and the weak part will be ruptured by the high-temperature and high-pressure gas. At this time, the high-temperature and high-pressure gas is quickly discharged through the explosion-proof valve and the weak part, rapidly reducing the gas pressure in the containment cavity, preventing the battery cell from exploding, and improving the safety of the battery cell. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the battery cell of this utility model;

[0020] Figure 2 yes Figure 1 A three-dimensional structural diagram of the casing of a single battery cell;

[0021] Figure 3 yes Figure 2 Top view of the shell;

[0022] Figure 4 yes Figure 2 A cross-sectional view of the shell;

[0023] Figure 5 yes Figure 4 An enlarged schematic diagram of the structure at point A of the shell;

[0024] Figure 6 This is an enlarged structural diagram of another embodiment of the housing at point A;

[0025] Figure 7 yes Figure 6 A top view of the base plate of another embodiment of the housing;

[0026] Figure 8 This is an assembly diagram of the housing and base plate of the battery cell of this utility model;

[0027] Figure 9 yes Figure 8 A magnified schematic diagram of the structure of a single battery cell at point B;

[0028] Figure 10 yes Figure 8 A magnified schematic diagram of the structure of a single battery cell at point C.

[0029] In the figure, 1 is the shell, 11 is the side plate, 12 is the bottom plate, 121 is the first plate, 122 is the second plate, 123 is the groove, 124 is the pressure relief groove, 13 is the receiving cavity, 14 is the pressure relief hole, 15 is the weak part, 16 is the groove, 2 is the explosion-proof valve, 3 is the first flow channel, 4 is the second flow channel, 5 is the third flow channel, 6 is the protective membrane, 61 is the air vent, 7 is the bottom support plate, 8 is the first gap, 9 is the second gap, Z is the first direction, Y is the second direction, and X is the third direction. Detailed Implementation

[0030] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0031] A preferred embodiment of a battery cell of this utility model is as follows: Figures 1 to 10 As shown, the battery cell includes a housing 1 and an explosion-proof valve 2. The battery cell also has an intersecting first direction Z and a second direction Y. In the embodiment, the first direction Z is the height direction of the battery cell, and the second direction Y is the width direction of the battery cell. The first direction Z is perpendicular to the second direction Y.

[0032] like Figure 1 and Figure 4 As shown, the housing 1 includes a side plate 11 and a bottom plate 12, which are perpendicular to each other. The side plate 11 and the bottom plate 12 form a receiving cavity 13, which is used to assemble electrode assemblies. The bottom plate 12 is also provided with a pressure relief hole 14, which penetrates the bottom plate 12 along a first direction Z. An explosion-proof valve 2 is fixedly connected to the bottom plate 12 and seals the pressure relief hole 14. When a battery cell experiences thermal runaway, the high-temperature and high-pressure gas generated in the receiving cavity 13 can rupture the explosion-proof valve 2 and be discharged in time from the pressure relief hole 14.

[0033] like Figure 2 and Figure 3 As shown, the base plate 12 is also provided with a weak part 15, which is located on the side of the base plate 12 facing the receiving cavity 13 along the first direction Z. The weak part 15 and the pressure relief hole 14 are spaced apart along the second direction Y. When a high-capacity lithium-ion battery experiences thermal runaway, the high-temperature and high-pressure gas accumulated in the receiving cavity 13 can also break through the weak part 15 after the explosion-proof valve 2 is ruptured, and can be vented simultaneously through the weak part 15 and the pressure relief hole 14, thereby improving the venting efficiency.

[0034] In this embodiment, there are two weak points 15. The two weak points 15 are arranged on both sides of the pressure relief hole 14 along the second direction Y. The size of the battery cell in the second direction Y is large. Increasing the number of weak points 15 can increase the exhaust path of high temperature and high pressure gas, accelerate the exhaust speed when the battery cell is thermally runaway, and improve the safety of the battery cell.

[0035] like Figure 3 As shown, the base plate 12 is further provided with a first flow channel 3, a second flow channel 4, and a third flow channel 5 on the side facing the receiving cavity 13 along the first direction Z. The first flow channel 3 connects the receiving cavity 13 with the weak part 15, the second flow channel 4 connects the receiving cavity 13 with the pressure relief hole 14, and the third flow channel 5 connects the weak part 15 with the pressure relief hole 14. The first flow channel 3, the second flow channel 4, and the third flow channel 5 form an exhaust channel for the battery cell from the receiving cavity 13 to the weak part 15 and the pressure relief hole 14. Furthermore, the third flow channel 5 connects the weak part 15 and the pressure relief hole 14, allowing high-temperature and high-pressure gas to flow between the weak part 15 and the pressure relief hole 14, thus ensuring the success rate of the weak part 15 explosion.

[0036] The battery cell has a weak part 15 on the bottom plate 12 of the casing 1, which is spaced apart from the pressure relief hole 14 along the second direction Y. When the battery cell experiences thermal runaway, high-temperature and high-pressure gas will enter the pressure relief hole 14 through the first flow channel 3, the weak part 15, the second flow channel 4, and the third flow channel 5. The explosion-proof valve 2 on the pressure relief hole 14 will be ruptured first to release the gas. When the gas in the containment cavity 13 accumulates in a short time and cannot be discharged through the explosion-proof valve 2, the gas pressure entering the weak part 15 through the first flow channel 3 will increase. The weak part 15 will be ruptured by the high-temperature and high-pressure gas. At this time, the high-temperature and high-pressure gas will be quickly discharged through the explosion-proof valve 2 and the weak part 15, rapidly reducing the gas pressure in the containment cavity 13, preventing the battery cell from exploding, and improving the safety of the battery cell.

[0037] In some embodiments, the base plate 12 includes a first plate 121 and a second plate 122 connected to each other along the second direction Y. Along the first direction Z, the size of the first plate 121 is L1 mm and the size of the second plate 122 is L2 mm, where L1 > L2, so that the base plate 12 forms a pressure relief groove 124 at the second plate 122, and the pressure relief groove 124 forms a weak part 15.

[0038] like Figure 5 As shown, the first plate 121 and the second plate 122 have a thickness along the first direction Z. The bottom plate 12 is formed by the first plate 121 and the second plate 122 with different thicknesses. Since the thickness of the second plate 122 is less than the thickness of the first plate 121, the bottom plate 12 naturally forms a pressure relief groove 124 at the second plate 122. Relative to the entire shell 1, the pressure relief groove 124 naturally forms a weak part 15, which ensures the overall strength of the shell 1 while simplifying the structural form of the weak part 15.

[0039] In some embodiments, the base plate 12 is provided with a groove 123, the groove 123 forms a weak part 15, and the outline shape of the groove 123 in the cross section perpendicular to the first direction Z is at least one of polygonal, annular, and racetrack-shaped.

[0040] like Figure 6 and Figure 7 As shown, the groove 123 forms a closed structure around the first direction Z, and it does not penetrate the base plate 12 along the first direction Z. The thickness of the base plate 12 is small at the groove 123, and the resulting weak part 15 is easy to process. In this embodiment, the thickness of the base plate 12 is the same at all positions except for the groove 123. The contour shape of the groove 123 in the cross section perpendicular to the first direction Z can also be at least one of polygon, ring, and racetrack shape.

[0041] In some embodiments, the base plate 12 is further provided with a groove 16 along the first direction Z. The groove 16 is provided on the side of the base plate 12 away from the weak part 15, and the weak part 15 is disposed opposite to the groove 16 along the first direction Z.

[0042] like Figure 2 As shown, a notch 16 is provided on the side of the base plate 12 away from the weak part 15. The weak part 15 is positioned opposite to the notch 16, which further reduces the thickness of the base plate 12 at the position opposite to the weak part 15. This ensures that high-temperature and high-pressure gas can smoothly break through the weak part 15, preventing the metal casing 1 from melting or the battery cell from exploding if the weak part 15 fails to open in time during thermal runaway of the battery cell.

[0043] In some embodiments, the notch 16 includes one of a semi-circle, an I-shape, or a wave shape.

[0044] Semicircular, I-shaped, or wavy shapes are commonly used for the structure of the notch 16, and their processing technology is mature and convenient. In this embodiment, the notch 16 is specifically semicircular, and the notches 16 corresponding to the two weak parts 15 are symmetrically arranged.

[0045] In some embodiments, the battery cell further includes a protective film 6, which is attached to the base plate 12, and the orthographic projection of the protective film 6 onto the base plate 12 along the first direction Z covers the groove 16.

[0046] like Figure 1 As shown, a protective film 6 is attached to the base plate 12 to cover the scratches 16. The protective film 6 can prevent the scratches 16 on the base plate 12 of other battery cells adjacent to the thermally runaway battery cell from being contaminated and corroded by the electrolyte.

[0047] In some embodiments, the protective film 6 is further provided with an air guide hole 61, which penetrates the protective film 6 along the first direction Z, and the air guide hole 61 partially overlaps with the groove 16 along the first direction Z.

[0048] A vent 61 is provided on the protective film 6, and the vent 61 partially overlaps with the groove 16 along the first direction Z. This ensures that the groove 16 on the base plate 12 maintains contact with the normal external atmospheric pressure, allowing high-temperature and high-pressure gas to successfully blast the weak part 15. In addition, the partial overlap of the vent 61 and the groove 16 prevents electrolyte from other battery cells from corroding and damaging the groove 16 through the vent 61.

[0049] In this embodiment, the air guide hole 61 is a continuous semi-circular structure. In other embodiments, the air guide hole 61 may also be a discontinuous toothed shape, or it may be circular or wavy.

[0050] In some embodiments, the battery cell further includes a bottom support plate 7, which is disposed in the receiving cavity 13. Along the second direction Y, the bottom support plate 7 and the side plate 11 have a first gap 8. Along the third direction X, the bottom support plate 7 and the side plate 11 have a second gap 9. The first flow channel 3 is connected to the first gap 8 and the second gap 9, respectively. The second flow channel 4 is connected to the second gap 9. The first direction Z, the second direction Y and the third direction X intersect each other.

[0051] like Figures 8 to 10 As shown, there is a first gap 8 and a second gap 9 between the bottom support plate 7 and the side plate 11 of the battery cell. The first gap 8 and the second gap 9 form an exhaust channel to ensure that the receiving cavity 13 is connected to the first flow channel 3 and the second flow channel 4, so that the gas in the receiving cavity 13 can enter the first flow channel 3 and the second flow channel 4 and be discharged from the pressure relief hole 14 and the weak part 15.

[0052] In some embodiments, the third flow channel 5 extends along the second direction Y, the second flow channel 4 extends along the third direction X, and there are multiple first flow channels 3, with some first flow channels 3 extending along the second direction Y and some first flow channels 3 extending along the third direction X.

[0053] The battery cell has a large size in the second direction Y. At the same time, the first flow channel 3 extending in the second direction Y and the third direction X is set to connect the weak part 15, which can increase the number of exhaust channels, so that high temperature and high pressure gas can quickly enter the weak part 15 and the pressure relief hole 14, thereby improving the exhaust efficiency.

[0054] This utility model also provides a preferred embodiment of a battery pack, including a battery cell. The specific structure of the battery cell is the same as that of the battery cell described in any of the above embodiments, and will not be repeated here.

[0055] In summary, this utility model provides a battery cell and a battery pack. The bottom plate of the casing has a weak portion spaced apart from the pressure relief hole along a second direction. When the battery cell experiences thermal runaway, high-temperature, high-pressure gas enters the pressure relief hole through the first flow channel, the weak portion, the second flow channel, and the third flow channel, first rupturing the explosion-proof valve on the pressure relief hole to release gas. When gas accumulates in the containment cavity for a short time and cannot be discharged through the explosion-proof valve, the gas pressure entering the weak portion through the first flow channel increases, causing the weak portion to be ruptured by the high-temperature, high-pressure gas. At this time, the high-temperature, high-pressure gas is quickly discharged through the explosion-proof valve and the weak portion, rapidly reducing the gas pressure in the containment cavity, preventing the battery cell from exploding, and improving the safety of the battery cell.

[0056] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A battery cell, characterized in that, The battery cell has intersecting first and second directions, and the battery cell includes: The housing includes a side plate and a bottom plate, the side plate and the bottom plate forming a receiving cavity, the bottom plate is provided with a pressure relief hole, the pressure relief hole penetrates the bottom plate along a first direction, and the bottom plate is also provided with a weak part on the side facing the receiving cavity, and along a second direction, the weak part and the pressure relief hole are spaced apart; An explosion-proof valve is fixedly connected to the base plate and seals the pressure relief hole. The bottom plate is further provided with a first flow channel, a second flow channel and a third flow channel on the side facing the receiving cavity. The first flow channel connects the receiving cavity and the weak part, the second flow channel connects the receiving cavity and the pressure relief hole, and the third flow channel connects the weak part and the pressure relief hole.

2. The battery cell according to claim 1, characterized in that, The base plate includes a first plate and a second plate that are connected to each other along the second direction. Along the first direction, the size of the first plate is L1 mm and the size of the second plate is L2 mm, where L1 > L2, so that the base plate forms a pressure relief groove at the second plate, and the pressure relief groove forms the weak part.

3. The battery cell according to claim 1, characterized in that, The base plate is provided with a groove, which forms the weak part. The outline shape of the groove in the cross section perpendicular to the first direction is at least one of polygon, ring, and racetrack shape.

4. The battery cell according to any one of claims 1-3, characterized in that, The base plate is also provided with grooves along the first direction. The grooves are located on the side of the base plate away from the weak part, and the weak part is arranged opposite to the grooves along the first direction.

5. The battery cell according to claim 4, characterized in that, The grooves include one of the following: semi-circular, I-shaped, or wavy.

6. The battery cell according to claim 4, characterized in that, The battery cell also includes a protective film, which is attached to the base plate, and the orthographic projection of the protective film onto the base plate along the first direction covers the groove.

7. The battery cell according to claim 6, characterized in that, The protective film is also provided with air guide holes, which penetrate the protective film along the first direction, and the air guide holes partially overlap with the grooves along the first direction.

8. The battery cell according to any one of claims 1-3, characterized in that, The battery cell also includes a bottom support plate disposed in the receiving cavity. Along the second direction, the bottom support plate has a first gap with the side plate. Along the third direction, the bottom support plate has a second gap with the side plate. The first flow channel is connected to the first gap and the second gap, respectively. The second flow channel is connected to the second gap. The first direction, the second direction and the third direction intersect each other.

9. The battery cell according to claim 8, characterized in that, The third flow channel extends along the second direction, the second flow channel extends along the third direction, and there are multiple first flow channels, some of which extend along the second direction and some of which extend along the third direction.

10. A battery pack, characterized in that, Includes the battery cell described in any one of claims 1-9.

Images