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, the single battery comprises a shell, the shell is provided with a pressure relief hole and an accommodating cavity, and the pressure relief hole penetrates through the shell along the first direction and is communicated with the accommodating cavity; the explosion-proof valve is fixedly connected with the shell and seals the pressure relief hole, the explosion-proof valve is provided with a plurality of guide grooves, and the guide grooves are distributed in a radial shape; the adhesive layer is attached to the side, deviating from the containing cavity in the first direction, of the shell; and the protective cover is arranged on the side, away from the anti-explosion valve in the first direction, of the adhesive layer, the protective cover is connected with the adhesive layer, the protective cover is provided with an exhaust hole, and the exhaust hole and the pressure relief hole are oppositely arranged in the first direction. When the explosion-proof valve is opened due to thermal runaway, the explosion-proof valve is broken from the guide groove, and the cracking piece is in a large block shape, so that the explosion-proof valve is prevented from being in a small fragment or powder shape; the protective cover is fixedly adhered to the shell through the adhesive layer, and the protective cover can prevent the splinters from splashing.

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] The battery pack is a core component of new energy vehicles, primarily composed of multiple interconnected lithium-ion batteries. During use, changes in the operating environment and lifespan of the lithium-ion batteries, as well as impacts caused by accidents such as traffic accidents, can lead to thermal anomalies within the battery, generating high-temperature, high-pressure substances. In such cases, it is crucial to promptly and quickly release these high-temperature, high-pressure substances. Lithium-ion batteries are typically equipped with explosion-proof valves. When the gas pressure inside the battery reaches the valve's opening pressure, the gas forces its way through, thus releasing the pressure.

[0003] Existing explosion-proof valves are usually made of aluminum diaphragms. When the internal pressure of a lithium-ion battery forces open the explosion-proof valve, the aluminum diaphragm breaks under pressure and splashes. The fragments of the aluminum diaphragm move randomly during the splashing. As metal parts, the fragments pose a risk of short circuit when they splash onto the surrounding lithium-ion batteries, causing thermal runaway in the surrounding lithium-ion batteries and affecting the safety of the battery pack. Utility Model Content

[0004] The purpose of this invention is to provide a single battery cell to solve the problem of fragments affecting battery safety after the explosion-proof valve of a lithium-ion battery is opened in the prior art; this invention also provides a battery pack using this single battery cell.

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

[0006] The housing has a pressure relief hole and a receiving cavity, the pressure relief hole penetrating the housing along the first direction and communicating with the receiving cavity;

[0007] An explosion-proof valve is fixedly connected to the housing and seals the pressure relief hole. The explosion-proof valve is provided with multiple guide grooves, which are radially distributed.

[0008] An adhesive layer is attached to the outer shell on the side opposite to the receiving cavity along the first direction;

[0009] A protective cover is disposed on the side of the adhesive layer away from the explosion-proof valve along the first direction. The protective cover is connected to the adhesive layer and has an exhaust hole. The exhaust hole and the pressure relief hole are arranged opposite to each other along the first direction.

[0010] In some embodiments, the battery cell further has a second direction and a third direction, the first direction, the second direction, and the third direction being perpendicular to each other, the guide groove having a first groove, a second groove, and a third groove, the first groove extending along the second direction, the second groove extending along the third direction, and multiple first grooves spaced apart along the third direction, the first grooves at both ends intersecting with the second grooves and the third grooves along the third direction.

[0011] In some embodiments, the battery cell further has a second direction and a third direction, the first direction, the second direction, and the third direction being perpendicular to each other, and the guide groove having a first groove, a second groove, and a third groove, the first groove extending along the second direction, the second groove extending along the third direction, and the first groove, the second groove, and the third groove intersecting at a point.

[0012] In some embodiments, the explosion-proof valve is further provided with reinforcing ribs that extend around the first direction and are connected to each of the guide grooves.

[0013] In some embodiments, the pressure relief hole has a hole wall extending from the radial center of the guide groove to the hole wall, and the size of the guide groove decreases along the first direction.

[0014] In some embodiments, the guide groove has a gap between one end near the hole wall and the hole wall.

[0015] In some embodiments, the housing includes a bottom plate, a side plate, and a cover plate, wherein the bottom plate, the side plate, and the cover plate enclose the receiving cavity, and the pressure relief hole is provided on the bottom plate or the cover plate.

[0016] In some embodiments, along the first direction, there is a gap between the explosion-proof valve and the protective cover, the size of which is H mm, and along the first direction, the size of the base plate or the cover plate is L mm, satisfying: H > L.

[0017] In some embodiments, the adhesive layer has a central hole that extends through the adhesive layer along the first direction, and the central hole and the vent hole are disposed opposite to each other along the first direction.

[0018] In some embodiments, the protective cover is a high-silica fabric.

[0019] This utility model also provides a battery pack, including the battery cells described in any of the above technical solutions.

[0020] Compared with the prior art, the battery cell and battery pack of this utility model embodiment have the following advantages: Because the explosion-proof valve is provided with a guide groove, when the explosion-proof valve opens due to thermal runaway, the explosion-proof valve breaks first from the guide groove. The radial guide groove ensures that the explosion-proof valve shatters into large pieces when it explodes, preventing the explosion-proof valve from becoming small fragments or powder. Furthermore, a protective cover is attached to the outer shell with an adhesive layer, and the protective cover has vent holes that are opposite to the pressure relief hole in the first direction. The vent holes ensure the ventilation efficiency after the explosion-proof valve opens, allowing the explosion-proof valve to open normally and release pressure. At the same time, the protective cover can prevent the shattered pieces from splashing and prevent the explosion-proof valve shattered pieces from contacting other battery cells and forming a short circuit, thus improving the safety of the battery pack. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a single battery cell of this utility model;

[0022] Figure 2 yes Figure 1 A cross-sectional view of the assembly of the explosion-proof valve, adhesive layer and protective cover of the battery cell;

[0023] Figure 3 yes Figure 1 A partially enlarged schematic diagram of the explosion-proof valve of a single battery cell;

[0024] Figure 4 yes Figure 1 A schematic diagram of the structure of the protective cover for a single battery cell;

[0025] Figure 5 yes Figure 1 A schematic diagram of the adhesive layer structure of a single battery cell;

[0026] Figure 6 This is a schematic diagram of the structure of the explosion-proof valve of the battery cell of this utility model when it is located on the base plate;

[0027] Figure 7 This is a schematic diagram of the state of the explosion-proof valve of the battery cell of this utility model when it is open;

[0028] Figure 8 This is a schematic diagram of another embodiment of the explosion-proof valve for a battery cell of this utility model;

[0029] Figure 9 yes Figure 8 A cross-sectional view of an explosion-proof valve.

[0030] In the diagram, 1 is the outer shell, 11 is the pressure relief hole, 111 is the hole wall, 12 is the bottom plate, 13 is the cover plate, 14 is the receiving cavity, 15 is the side plate, 2 is the explosion-proof valve, 21 is the guide groove, 211 is the first groove, 212 is the second groove, 213 is the third groove, 22 is the reinforcing rib, 3 is the adhesive layer, 31 is the center hole, 4 is the protective cover, 41 is the exhaust hole, Z is the first direction, Y is the second direction, and X is the third direction. Detailed Implementation

[0031] 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.

[0032] A preferred embodiment of a battery cell of this utility model is as follows: Figures 1 to 9 As shown, the battery cell includes a casing 1, an explosion-proof valve 2, an adhesive layer 3, and a protective cover 4. The battery cell has a first direction Z. In this embodiment, the battery cell is a square lithium battery, the casing 1 is rectangular, and the first direction Z is the height direction of the battery cell.

[0033] The outer casing 1 is made of aluminum and has a pressure relief hole 11 and a receiving cavity 14. The pressure relief hole 11 penetrates the outer casing 1 along a first direction Z and communicates with the receiving cavity 14. The receiving cavity 14 is used to accommodate the electrode assembly and is cuboid in shape. The pressure relief hole 11 is an elongated hole extending along the width direction of the outer casing 1. The pressure relief hole 11 is used to install an explosion-proof valve 2 to quickly release the high-pressure gas inside the outer casing 1 in the event of thermal runaway of a battery cell.

[0034] The explosion-proof valve 2 is fixedly connected to the outer casing 1 and seals the pressure relief hole 11. The explosion-proof valve 2 is provided with a guide groove 21. In this embodiment, the explosion-proof valve 2 is an aluminum sheet, and the thickness of the explosion-proof valve 2 at the guide groove 21 is less than its overall thickness. When a battery cell explodes, the aluminum sheet on the surface of the explosion-proof valve 2 can break open first at the guide groove 21, and the broken pieces are large pieces, rather than small fragments or powder, which facilitates the collection of large pieces.

[0035] There are multiple guide grooves 21, which are arranged radially. The radial arrangement of the guide grooves 21 makes it easier for the intersection of the guide grooves 21 to be torn apart when the explosion-proof valve 2 bursts. At the same time, the overall shape of the fragment is rectangular or triangular, and the connection between the root of the fragment and the overall structure of the explosion-proof valve 2 is strong, so it will not break and cause splashing.

[0036] The adhesive layer 3 is attached to the side of the outer casing 1 facing away from the receiving cavity 14 along the first direction Z, that is, the adhesive layer 3 is located on the outside of the outer casing 1. The protective cover 4 is disposed on the side of the adhesive layer 3 facing away from the explosion-proof valve 2 along the first direction Z. The protective cover 4 is connected to the adhesive layer 3, that is, the protective cover 4 is bonded and fixed to the outer casing 1 through the adhesive layer 3. When the explosion-proof valve 2 ruptures, the fragment is blocked by the protective cover 4, which can prevent the fragment from contacting other battery cells in the battery pack and causing a short circuit in the battery cells, thus delaying the rate of combustion and explosion of the battery pack and improving the safety of the battery pack.

[0037] The protective cover 4 also has a vent 41, which penetrates the protective cover 4 along the first direction Z. The vent 41 and the pressure relief hole 11 are arranged opposite each other along the first direction Z. The vent 41 can meet the normal pressure relief and venting area requirements of the explosion-proof valve 2. In this embodiment, there are multiple vents 41, and each vent 41 is arranged in an array on the protective cover 4. The arrangement of multiple vents 41 in an array on the protective cover 4 can increase the aesthetics of the vents 41 and meet the venting area requirements.

[0038] Because the explosion-proof valve 2 of this battery cell has a guide groove 21, when the explosion-proof valve 2 opens due to thermal runaway, the explosion-proof valve 2 breaks first from the guide groove 21. The radial guide groove 21 ensures that the explosion-proof valve 2 breaks into large pieces when it explodes, preventing the explosion-proof valve 2 from becoming small fragments or powder. In addition, the protective cover 4 is attached to the outer shell 1 with an adhesive layer 3, and the protective cover 4 is provided with an exhaust hole 41 opposite to the pressure relief hole 11 in the first direction Z. The exhaust hole 41 can ensure the ventilation efficiency after the explosion-proof valve 2 opens, so that the explosion-proof valve 2 can open normally and release pressure. At the same time, the protective cover 4 can prevent the fragments of the explosion-proof valve 2 from flying and preventing the fragments of the explosion-proof valve 2 from contacting other battery cells and forming a short circuit, thereby improving the safety of the battery pack.

[0039] In some embodiments, the battery cell further has a second direction Y and a third direction X, the first direction Z, the second direction Y, and the third direction X are perpendicular to each other, and the guide groove 21 has a first groove 211, a second groove 212 and a third groove 213. The first groove 211 extends along the second direction Y, the second groove 212 extends along the third direction X, and multiple first grooves 211 are spaced apart along the third direction X. Along the third direction X, the first grooves 211 at both ends intersect with the second grooves 212 and the third grooves 213.

[0040] In some embodiments, the battery cell also has a second direction Y and a third direction X, the first direction Z, the second direction Y, and the third direction X are perpendicular to each other, and the guide groove 21 has a first groove 211, a second groove 212 and a third groove 213. The first groove 211 extends along the second direction Y, the second groove 212 extends along the third direction X, and the first groove 211, the second groove 212 and the third groove 213 intersect at a point.

[0041] like Figure 8 As shown, in this embodiment, the second direction Y is the thickness direction of the battery cell, the third direction X is the width direction of the battery cell, the first groove 211 extends along the thickness direction of the battery cell, the second groove 212 extends along the width direction of the battery cell, and the third groove 213 intersects both the second direction Y and the third direction X. The first groove 211, the second groove 212 and the third groove 213 intersect at a point and form a cross shape, which makes the overall structure of the guide groove 21 simpler and easier to extrude.

[0042] like Figure 3 As shown, in this embodiment, the second direction Y is the thickness direction of the battery cell, and the third direction X is the width direction of the battery cell. The first groove 211 extends along the thickness direction of the battery cell, the second groove 212 extends along the width direction of the battery cell, and the third groove 213 is distributed at both ends of the explosion-proof valve 2 in the width direction of the battery cell. Since the explosion-proof valve 2 is racetrack-shaped, only the first groove 211 and the second groove 212 are provided in the rectangular area at its center, and the first groove 211, the second groove 212, and the third groove 213 are provided in the arc-shaped areas at both ends. This allows for a reasonable distribution of the guide grooves 21, resulting in uniform overall strength of the explosion-proof valve 2.

[0043] In some embodiments, the explosion-proof valve is further provided with a reinforcing rib 22, which extends around the first direction Z and connects to each guide groove 21.

[0044] like Figure 3 , Figure 8 and Figure 9 As shown, the reinforcing rib 22 can increase the overall strength of the explosion-proof valve 21 and prevent the explosion-proof valve 21 from bursting when it is bumped.

[0045] In some embodiments, the pressure relief hole 11 has a hole wall 111, and the size of the guide groove 21 decreases along the first direction Z in the direction from the radial center of the guide groove 21 to the hole wall 111.

[0046] like Figure 9 As shown, the dimension of the guide groove 21 along the first direction Z is its depth. From the radiation center of the guide groove 21 to the hole wall 111, the dimension of the guide groove 21 along the first direction Z decreases, so that the guide groove 21 has a slope. The depth of the guide groove is the greatest near the radiation center, which makes it easy for the explosion-proof valve 21 to be torn from this point.

[0047] In some embodiments, the guide groove 21 has a gap between one end near the hole wall 111 and the hole wall 111.

[0048] like Figure 3 , Figure 8 and Figure 9As shown, there is a gap X between the guide groove 21 and the hole wall 111 of the pressure relief hole 11. This gap allows the root of the rupture fragment to connect with the periphery of the explosion-proof valve 2 when the battery cell experiences thermal runaway and the explosion-proof valve 2 explodes along the guide groove 21. The rupture fragment will not completely break off from the explosion-proof valve 2, preventing large pieces of the rupture fragment from flying everywhere.

[0049] In some embodiments, the housing 1 includes a bottom plate 12, a side plate 15, and a cover plate 13. The bottom plate 12, the side plate 15, and the cover plate 13 form a receiving cavity 14, and a pressure relief hole 11 is provided on the bottom plate 12 or the cover plate 13.

[0050] like Figure 1 and Figure 6 As shown, the pressure relief hole 11 can be provided on the bottom plate 12 or the cover plate 13 of the housing 1 to change the arrangement position of the explosion-proof valve 2. When the pressure relief hole 11 is provided on the bottom plate 12, the high-pressure gas is discharged through the explosion-proof valve 2 away from the cover plate 13, which can achieve electrical separation; when the pressure relief hole 11 is provided on the cover plate 13, it can prevent gas from accumulating at the cover plate 13 and prevent the connection between the cover plate 13 and the side plate 15 from being torn.

[0051] In some embodiments, along the first direction Z, there is a gap between the explosion-proof valve 2 and the protective cover 4, the size of which is H mm. Along the first direction Z, the size of the base plate 12 or the cover plate 13 is L mm, satisfying that H > L.

[0052] like Figure 2 As shown, the gap between the explosion-proof valve 2 and the protective cover 4 forms a space for accommodating the fragments of the explosion-proof valve 2. When the explosion-proof valve 2 tears, the torn fragments can be stored to prevent them from flying off.

[0053] Along the first direction Z, the gap is larger than the size of the base plate 12 or the cover plate 13, ensuring sufficient space to store the fragments in the first direction Z. In this embodiment, the explosion-proof valve 2 is concave, and is recessed into the receiving cavity 14 of the outer shell 1 along the first direction Z to ensure the gap between the explosion-proof valve 2 and the protective cover 4.

[0054] In some embodiments, the adhesive layer 3 has a central hole 31 that extends through the adhesive layer 3 along a first direction Z, and the central hole 31 and the vent hole 41 are disposed opposite to each other along the first direction Z.

[0055] The adhesive layer 3 is provided with a central hole 31 that is opposite to the vent hole 41 along the first direction Z. When the battery cell is thermally runaway, the central hole 31 can allow high-pressure gas to pass through, thus avoiding burning the adhesive layer 3.

[0056] In some embodiments, the protective cover 4 is a high-silica fabric.

[0057] When the explosion-proof valve 2 opens to release high-pressure gas due to thermal runaway of a single battery cell, flames are usually generated. According to experimental data and experience, the flame temperature is usually between 600-900℃. Therefore, the protective cover 4 needs to be heat-resistant to more than 900℃ and has the characteristics of fire resistance, insulation, and easy processing and opening.

[0058] Huolong high-silica cloth boasts advantages such as lightweight, softness like silk, high temperature resistance, good insulation, low thermal conductivity, good heat preservation, corrosion resistance, non-toxicity, and asbestos-free properties, exhibiting excellent environmental performance. In this embodiment, the Huolong high-silica cloth is selected with a thickness of 1.3mm. When the explosion-proof valve 2 is located at the bottom of the outer casing 1, the adhesive layer thickness at the bottom of the battery pack is 1.1mm, and the compression of the Huolong high-silica cloth is approximately 0.2mm, matching the adhesive layer thickness.

[0059] 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.

[0060] In summary, this utility model embodiment provides a battery cell and a battery pack. Because the explosion-proof valve has a guide groove, when the explosion-proof valve opens due to thermal runaway, the valve breaks open first from the guide groove. The radial guide groove ensures that the explosion-proof valve shatters into large pieces upon explosion, preventing the valve from becoming small fragments or powder. Furthermore, a protective cover is glued to the outer shell using an adhesive layer, and the protective cover has vent holes aligned with the pressure relief hole in a first direction. These vent holes ensure efficient ventilation after the explosion-proof valve opens, allowing it to open normally and release pressure. Simultaneously, the protective cover prevents the shattered pieces from splashing and contacting other battery cells, thus preventing short circuits and improving the safety of the battery pack.

[0061] 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 a first orientation (Z), and the battery cell includes: The outer casing (1) has a pressure relief hole (11) and a receiving cavity (14), the pressure relief hole (11) penetrates the outer casing (1) along the first direction (Z) and communicates with the receiving cavity (14); An explosion-proof valve (2) is fixedly connected to the outer shell (1) and seals the pressure relief hole (11). The explosion-proof valve (2) is provided with a guide groove (21). There are multiple guide grooves (21), and each guide groove (21) is radially distributed. An adhesive layer (3) is attached to the outer shell (1) on the side opposite to the receiving cavity (14) along the first direction (Z); A protective cover (4) is provided on the side of the adhesive layer (3) away from the explosion-proof valve (2) along the first direction (Z). The protective cover (4) is connected to the adhesive layer (3). The protective cover (4) has an exhaust hole (41). The exhaust hole (41) and the pressure relief hole (11) are arranged opposite to each other along the first direction (Z).

2. The battery cell according to claim 1, characterized in that, The battery cell also has a second direction (Y) and a third direction (X), the first direction (Z), the second direction (Y), and the third direction (X) are perpendicular to each other. The guide groove (21) has a first groove (211), a second groove (212), and a third groove (213). The first groove (211) extends along the second direction (Y), the second groove (212) extends along the third direction (X), and multiple first grooves (211) are spaced apart along the third direction (X). Along the third direction (X), the first grooves (211) at both ends intersect with the second grooves (212) and the third grooves (213).

3. The battery cell according to claim 1, characterized in that, The battery cell also has a second direction (Y) and a third direction (X), the first direction (Z), the second direction (Y), and the third direction (X) being perpendicular to each other. The guide groove (21) has a first groove (211), a second groove (212), and a third groove (213). The first groove (211) extends along the second direction (Y), the second groove (212) extends along the third direction (X), and the first groove (211), the second groove (212), and the third groove (213) intersect at a point.

4. The battery cell according to any one of claims 1-3, characterized in that, The explosion-proof valve is also provided with reinforcing ribs (22), which extend around the first direction (Z) and are connected to each of the guide grooves (21).

5. The battery cell according to any one of claims 1-3, characterized in that, The pressure relief hole (11) has a hole wall (111) extending from the radial center of the guide groove (21) to the hole wall (111), and the size of the guide groove (21) decreases along the first direction (Z).

6. The battery cell according to claim 5, characterized in that, The guide groove (21) has a gap between its end near the hole wall (111) and the hole wall (111).

7. The battery cell according to any one of claims 1-3, characterized in that, The outer casing (1) includes a bottom plate (12), a side plate (15) and a cover plate (13). The bottom plate (12), the side plate (15) and the cover plate (13) enclose the receiving cavity (14). The pressure relief hole (11) is provided on the bottom plate (12) or the cover plate (13).

8. The battery cell according to claim 7, characterized in that, Along the first direction (Z), there is a gap between the explosion-proof valve (2) and the protective cover (4), the size of which is H mm. Along the first direction (Z), the size of the base plate (12) or the cover plate (13) is L mm, satisfying: H > L.

9. The battery cell according to any one of claims 1-3, characterized in that, The adhesive layer (3) has a central hole (31) that penetrates the adhesive layer (3) along the first direction (Z) and the central hole (31) and the vent hole (41) are arranged opposite to each other along the first direction (Z).

10. The battery cell according to any one of claims 1-3, characterized in that, The protective cover (4) is made of high silica cloth.

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

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