Battery cell and battery module

Abstract

The invention relates to the technical field of batteries, and discloses a battery cell and a battery pack, and the battery cell comprises a shell, a pole group, at least two sections of high-temperature-resistant layers and a pressure relief structure. The battery cell with the structure is applied to the battery pack, and when one or some battery cells in the battery pack are thermally out of control, under the limiting action of the high-temperature-resistant layer, high-temperature eruptions at all positions in the pole group move to the blank area of the pole group, so that the high-temperature eruptions can move to the blank area and the pressure relief structure along a preset exhaust path. The high-temperature substance gathered from each position in the pole group to the blank area heats the pole group in the blank area, after the temperature of the area rises to be above the melting point of the pole group, the blank area of the pole group is melted, the pole group is broken, and the battery cell is disconnected with other battery cells in the battery pack, so that the whole battery pack system cannot form a closed electric loop; the battery pack is effectively prevented from generating large-area short-circuit current, and the safety performance of the battery pack after the battery cell is in thermal runaway is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell and a battery module. Background Art

[0002] With the development of new energy vehicles, the requirements for the charging rate and safety performance of battery packs are getting higher and higher. At present, the charging rate of battery packs has been increased from 2C to 3C, and then from 3C to 6C, achieving fast charging and long battery life. Since the chemical properties of high-rate charging cells are relatively active, in order to ensure safety, the safety protection of the entire battery pack needs to be improved accordingly. Existing battery packs have a greater risk of short circuit after thermal runaway of the battery cells, resulting in lower safety of the battery pack system. Summary of the invention

[0003] In view of this, the present invention provides a battery cell and a battery module to solve the problem in the prior art that the battery pack is prone to short circuit during thermal runaway, resulting in low system safety.

[0004] In a first aspect, the present invention provides a battery cell, comprising:

[0005] case;

[0006] A pole group, disposed in the housing;

[0007] At least two sections of high temperature resistant layers are wrapped around the pole group at intervals along the y direction of the pole group; the pole groups between adjacent high temperature resistant layers form a blank area;

[0008] A pressure relief structure is provided on the shell, and the pressure relief structure is located within the projection range of the blank area on the shell.

[0009] Beneficial effects: The battery cell of this structure is used in a battery pack, and multiple battery cells in the battery pack are electrically connected. When one or some battery cells in the battery pack thermally run away, a violent chemical reaction occurs inside the battery cell, and the pressure inside the shell rises to the pressure threshold at which the pressure relief structure opens, and the pressure relief structure opens. Since only part of the outer wall of the pole group is wrapped with the high-temperature resistant layer, and the blank area is not wrapped with the high-temperature resistant layer, the high-temperature resistant layer is resistant to high temperatures and will not be damaged at high temperatures, and the high-temperature eruption generated by thermal runaway cannot break through the high-temperature resistant layer. The blank area is close to the pressure relief structure, and the pressure in the blank area is relatively small. At the same time, under the restriction of the high-temperature resistant layer, the high-temperature eruption at various positions in the pole group moves to the blank area of ​​the pole group, so that the high-temperature eruption can move along the preset exhaust path to the blank area and the pressure relief structure. The high-temperature material gathered from various places in the electrode group to the blank area heats the electrode group in the blank area. After the temperature of the area rises above the melting point of the electrode group, the blank area of ​​the electrode group melts and the electrode group breaks. The battery cell is disconnected from other battery cells in the battery pack, making it impossible for the entire battery pack system to form a closed electrical loop, effectively preventing the battery pack from generating large-area short-circuit current, effectively reducing the risk factor of the battery pack after thermal runaway of the battery cell, and greatly improving the safety performance of the battery pack after thermal runaway of the battery cell.

[0010] In an optional embodiment, the pressure relief structure is provided on the shell on at least one side of the two ends of the blank area along the z-direction.

[0011] Beneficial effects: Pressure relief structures are set at both ends of the blank area, which is beneficial to improving the exhaust efficiency when the battery cell is in thermal runaway; at the same time, it is beneficial to balance the pressure in the blank area of ​​the electrode group, so that the high-temperature eruption material flows evenly towards the two ends of the blank area after reaching the blank area, so that the high-temperature eruption material is evenly distributed in the blank area, which is beneficial to balanced heating and melting at various positions in the blank area, ensuring that the blank area is completely disconnected along the z direction, and effectively avoiding large-area short-circuit current in the battery pack system.

[0012] In an optional embodiment, the shell has a long side and a wide side, and the long side of the shell extends along the y direction.

[0013] Beneficial effects: The high temperature resistant layer divides the pole group into multiple sections along the length direction of the pole group, and the area between adjacent high temperature resistant layers forms a blank area, which is conducive to shortening the movement path of high temperature eruption materials along the length direction of the pole group, ensuring rapid exhaust of the battery cell, and is conducive to the rapid gathering of high temperature eruption materials in the blank area and melting the pole group, preventing secondary insulation short circuits in the battery pack, and eliminating the risk of further harm caused by thermal runaway of the battery cell in a short time. At least two sections of high temperature resistant layers are arranged at intervals along the length direction of the pole group, and the blank area extends along the width direction of the pole group, which is conducive to shortening the fracture path of the pole group and ensuring that the pole group is completely fractured along its width direction.

[0014] In an optional embodiment, the length of the shell is L, L<300 mm, the high temperature resistant layer is provided with two sections, the blank area is provided with one section, and the pressure relief structure is provided on the shell corresponding to the blank area.

[0015] Beneficial effects: Since the overall length of the battery cell is relatively short, setting up a blank area and a pressure relief structure can ensure the exhaust of the battery cell in the event of thermal runaway, while ensuring that the high-temperature eruption material heats the electrode group in the blank area, thereby avoiding the risk of further short circuit in the battery pack due to the electrode group melting for too long; in addition, by controlling the number of pressure relief structures, the production cost of the battery cell and the battery pack can be saved.

[0016] In an optional embodiment, L≥300mm, the high temperature resistant layer is provided with at least three sections, the blank area is provided with at least two sections, and the pressure relief structure is provided on the shell corresponding to each section of the blank area.

[0017] Beneficial effect: The length of the battery cell is relatively long. By providing at least two blank areas and a pressure relief structure in the length direction of the electrode group, the movement path of the high-temperature eruption material can be shortened, ensuring the exhaust effect and the fusing effect of the electrode group.

[0018] In an optional embodiment, the wide side of the shell extends along the z-direction, and at least two of the pressure relief structures located on the same side of the two sides of the shell in the z-direction are arranged at equal intervals along the y-direction of the shell.

[0019] Beneficial effect: This arrangement can make the pressure relief structure evenly distributed, ensure the uniformity of the movement path of the high-temperature eruption materials in various parts of the pole group, and ensure the exhaust effect and the fracture effect of the pole group.

[0020] In an optional implementation, the distance between the pressure relief structure and an edge of a projection of the high temperature resistant layer on the shell on the side where the pressure relief structure is located is d, and d≤2 mm.

[0021] Beneficial effect: d≤2mm, by reducing the distance between the pressure relief structure and the high temperature resistant layer, the high temperature eruption material can be better gathered on the pole group between the two oppositely arranged pressure relief structures, thereby ensuring the heating effect and fusing effect of the pole group.

[0022] In an optional embodiment, the battery cell includes a blade battery, and the positive output pole and the negative output pole of the blade battery are respectively arranged at two ends of the shell in the y direction.

[0023] In an optional embodiment, the material of the high temperature resistant layer includes a high temperature resistant insulating material;

[0024] And / or, the melting point difference between the high temperature resistant layer and the blank area is 400°C-1000°C.

[0025] Beneficial effects: The high temperature resistant layer has the dual effects of high temperature resistance and insulation. While ensuring that the high temperature and high pressure eruption materials move directional to the blank area with high temperature resistance, it can also play a good insulating role between the pole group and the shell.

[0026] In a second aspect, the present invention further provides a battery pack, comprising any one of the above-mentioned battery cells, wherein a plurality of the battery cells are electrically connected. The battery pack comprises a battery cell, and has the same technical effect as the battery cell, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 is a schematic diagram of a battery cell according to an embodiment of the present invention;

[0029] Figure 2 for Figure 1 Schematic diagram of the coordination between the intermediate electrode group and the high temperature resistant layer;

[0030] Figure 3 A diagram showing the movement path of high-temperature gas during thermal runaway of a battery cell according to an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of a pole group rupture during thermal runaway of a battery cell according to an embodiment of the present invention;

[0032] Figure 5 for Figure 1 Schematic diagram of the middle shell;

[0033] Figure 6 is a schematic diagram of a battery cell according to an embodiment of the present invention;

[0034] Figure 7 A schematic diagram of another battery cell of different lengths according to an embodiment of the present invention;

[0035] Figure 8 A schematic diagram of another battery cell with different lengths according to an embodiment of the present invention;

[0036] Fig. 9 A schematic diagram of another battery cell with different lengths according to an embodiment of the present invention;

[0037] Fig.10 is a schematic diagram of another battery cell according to an embodiment of the present invention;

[0038] Fig.11 is a schematic diagram of another battery cell according to an embodiment of the present invention;

[0039] Fig.12 is a schematic diagram of a battery pack according to an embodiment of the present invention;

[0040] Fig.13 The present invention is a schematic diagram of a circuit breaker after a certain electrode group in a battery pack is disconnected.

[0041] Description of reference numerals:

[0042] 1. Shell; 2. Pole group; 21. Blank area; 3. High temperature resistant layer; 4. Pressure relief structure; 5. Positive output pole; 6. Negative output pole. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0044] The chemical properties of the high-rate charging cells in the related technology are relatively active. After the cells thermally run away, the battery pack system is prone to secondary insulation short-circuit problems due to the electrical connection between the cells in the battery pack. The battery pack will generate a large area of ​​short-circuit current, causing serious safety hazards and resulting in low safety of the battery pack system.

[0045] Combine the following Figures 1 to 13 , describing an embodiment of the present invention.

[0046] According to an embodiment of the present invention, on the one hand, a battery cell is provided, comprising a housing 1, an electrode group 2, at least two sections of high temperature resistant layers 3 and a pressure relief structure 4. The electrode group 2 is arranged in the housing 1; at least two sections of high temperature resistant layers 3 are wrapped around the outside of the electrode group 2 at intervals along the y direction of the electrode group 2; the electrode group 2 between adjacent high temperature resistant layers 3 forms a blank area 21; the pressure relief structure 4 is arranged on the housing 1, and the pressure relief structure 4 is located within the projection range of the blank area 21 on the housing 1.

[0047] The battery cell of this structure is used in a battery pack, and multiple battery cells in the battery pack are electrically connected. When one or some battery cells in the battery pack thermally run away, a violent chemical reaction occurs inside the battery cell, and the pressure inside the shell 1 increases to the pressure threshold at which the pressure relief structure 4 opens, and the pressure relief structure 4 opens. Since the high temperature resistant layer 3 is wrapped only in part of the outer wall of the pole group 2, and the blank area 21 is not wrapped in the high temperature resistant layer 3, the high temperature resistant layer 3 is resistant to high temperature and will not be damaged at high temperature, and the high temperature ejecta generated by thermal runaway cannot break through the high temperature resistant layer 3. The blank area 21 is close to the pressure relief structure 4, and the pressure in the blank area 21 is relatively small. Figure 3 and Fig.12 As shown, under the limiting effect of the high temperature resistant layer 3, the high temperature ejecta at various positions in the electrode group 2 move to the blank area 21 of the electrode group 2, so that the high temperature ejecta can move to the blank area 21 and the pressure relief structure 4 along the preset exhaust path. The high temperature substances gathered from various places in the electrode group 2 to the blank area 21 heat the electrode group 2 in the blank area 21. After the temperature of this area rises to above the melting point of the electrode group 2, the blank area 21 of the electrode group 2 melts, the electrode group 2 breaks, and the battery cell is disconnected from other battery cells in the battery pack, so that the entire battery pack system cannot form a closed electrical circuit, effectively avoiding the battery pack from generating a large area of ​​short-circuit current, effectively reducing the risk factor of the battery pack after the battery cell thermal runaway, and greatly improving the safety performance of the battery pack after the battery cell thermal runaway.

[0048] Optionally, in some embodiments, Figure 1 , Fig. 9 and Fig.10 As shown, the housing 1 at both ends of the blank area 21 along the z direction is provided with a pressure relief structure 4. The pressure relief structure 4 is provided at both ends of the blank area 21, which is beneficial to improving the exhaust efficiency when the battery cell is in thermal runaway; at the same time, it is beneficial to balance the pressure in the blank area 21 of the pole group 2, so that the high-temperature eruption material flows evenly toward the two ends of the blank area 21 (the two ends in the z direction) after reaching the blank area 21, so that the high-temperature eruption material is evenly distributed in the blank area 21, which is beneficial to the balanced heating and melting of each position of the blank area 21, ensuring that the blank area 21 is completely disconnected along the z direction, and effectively avoiding large-area short-circuit current in the battery pack system.

[0049] Alternatively, if Figure 1 As shown, the blank area 21 is arranged opposite to the pressure relief structure 4 on the shell 1 at both ends along the z direction. Such an arrangement is more conducive to the movement of high-temperature eruptive materials to the pole group 2 between the two oppositely arranged pressure relief structures 4, and is conducive to the fracture of the pole group 2 along the area between the two oppositely arranged pressure relief structures 4. The area between the two oppositely arranged pressure relief structures 4 is perpendicular to the y direction of the shell. Compared with the inclined arrangement of the fracture area of ​​the pole group 2 and the y direction of the shell, the vertical fracture of the pole group 2 is conducive to shortening the fracture path of the pole group 2, thereby shortening the fracture time of the pole group 2, thereby further improving the safety performance of the battery pack when the battery cell is thermally runaway.

[0050] In other embodiments, Fig.11 As shown, a pressure relief structure 4 is provided on the shell 1 on one of the two sides of the blank area 21 along the z-direction. The pressure relief structure 4 can be arranged at the lower part or the upper part of the shell in the z-direction.

[0051] like Figure 1 , Figure 5 and Fig. 9 As shown, in some embodiments, the shell 1 has a long side and a wide side, the long side of the shell extends in the y direction, the long side of the pole group 2 extends in the same direction as the long side of the shell 1, and the wide side of the pole group 2 extends in the same direction as the wide side of the shell 1. At least two sections of high temperature resistant layers 3 are arranged at intervals along the length direction of the pole group 2. The high temperature resistant layer 3 divides the pole group 2 into multiple sections along the length direction of the pole group 2, and the area between adjacent high temperature resistant layers 3 forms a blank area 21, which is conducive to shortening the movement path of the high temperature eruption along the length direction of the pole group 2, ensuring the rapid exhaust of the battery cell, and is conducive to the high temperature eruption quickly gathering in the blank area 21 and melting the pole group 2, preventing the battery pack from having a secondary insulation short circuit, and can eliminate the risk of further harm caused by thermal runaway of the battery cell in a short time. At least two sections of high temperature resistant layers 3 are arranged at intervals along the length direction of the pole group 2, and the blank area 21 extends along the width direction of the pole group 2, which is conducive to shortening the fracture path of the pole group 2 and ensuring that the pole group 2 is completely fractured along its width direction.

[0052] In other embodiments, the shell 1 has a long side and a wide side, the pole group 2 has a long side and a wide side, the wide side of the shell extends along the y direction, at least two sections of the high temperature resistant layer 3 are arranged at intervals along the width direction of the pole group 2, and the blank area 21 extends along the length direction of the pole group 2.

[0053] like Figure 6 As shown, in some embodiments, the length of the shell 1 is L, L < 300mm, the high temperature resistant layer 3 is provided with two sections, the blank area 21 is provided with one section, and the shell 1 corresponding to the blank area 21 is provided with a pressure relief structure 4. That is, when the length of the shell 1 is relatively short, a blank area 21 is provided on the pole group 2, and correspondingly, a pressure relief structure 4 is provided on the shell 1 at a position corresponding to the blank area 21. At this time, since the overall length of the battery cell is relatively short, the path for the high-temperature eruption on both sides of the blank area 21 to move to the blank area 21 is relatively short. The provision of a blank area 21 and a pressure relief structure 4 can ensure the exhaust of the battery cell when it is thermally runaway, and at the same time ensure that the high-temperature eruption heats the pole group 2 in the blank area 21, thereby avoiding the risk of further short circuit of the battery pack caused by the long melting time of the pole group 2; in addition, by controlling the number of pressure relief structures 4, the production cost of the battery cell and the battery pack is saved.

[0054] In other embodiments, Figure 7 and Figure 8As shown, when L ≥ 300 mm, the high temperature resistant layer 3 is provided with at least three sections, the blank area 21 is provided with at least two sections, and the housing 1 corresponding to each blank area 21 is provided with a pressure relief structure 4. At this time, the length of the battery cell is relatively long. By providing at least two blank areas 21 and the pressure relief structure 4 in the length direction of the electrode group 2, the movement path of the high temperature eruption can be shortened, and the exhaust effect and the fusing effect of the electrode group 2 can be ensured.

[0055] In some embodiments, for every 300 mm increase in the length of the battery cell, a blank area 21 and a pair of pressure relief structures 4 are added to the electrode group 2, and the two pressure relief structures 4 at both ends (both ends in the z direction) of each blank area 21 are arranged opposite to each other. The high temperature resistant layer 3 is arranged inwardly with both ends of the electrode group 2 to ensure that the blank areas 21 are all located in the internal area of ​​the electrode group 2, and to ensure that the blank areas 21 of the electrode group 2 can be disconnected from the inside after melting, thereby disconnecting the electrical connection of the battery cell, and then disconnecting the electrical connection of the battery cell with other batteries in the battery pack.

[0056] In some embodiments, Figure 7 and Figure 8 As shown, the wide side of the shell extends along the z direction, and at least two pressure relief structures 4 located on the same side of the shell 1 on both sides of the z direction are arranged at equal intervals along the y direction of the shell 1. This arrangement can make the pressure relief structures 4 evenly distributed, which can ensure the uniformity of the movement path of the high-temperature eruption materials in various locations in the pole group 2, and ensure the exhaust effect and the fracture effect of the pole group 2.

[0057] In some embodiments, Figures 1 to 4 As shown, the inner end of the high temperature resistant layer 3 facing the blank area 21 is flush, and the inner end face formed by the edges of the inner end of the high temperature resistant layer 3 facing the blank area 21 is parallel to the end face of the pole group 2. If the inner end of the high temperature resistant layer 3 is too far away from the pressure relief structure 4, and the strength of the pole group 2 between the pressure relief structure 4 and the high temperature resistant layer 3 is relatively weak, the high temperature eruption inside the pole group 2 is also easy to be ejected from the pole group 2 through the pole group 2 area between the pressure relief structure 4 and the high temperature resistant layer 3, resulting in the high temperature eruption being unable to effectively converge in the pole group 2 area between the two oppositely arranged pressure relief structures 4, and it is difficult to ensure the fusing effect of the pole group 2. In order to avoid this problem, as Figure 6 As shown, in some embodiments, the distance between the edge of the projection of the pressure relief structure 4 and the high temperature resistant layer 3 on the shell on the side where the pressure relief structure 4 is located is d, d≤2mm. By reducing the distance between the pressure relief structure 4 and the high temperature resistant layer 3, the high temperature eruption can be better gathered on the pole group 2 between the two relatively arranged pressure relief structures 4, thereby ensuring the heating effect and fusing effect of the pole group 2.

[0058] In other embodiments, the inner end of the high temperature resistant layer 3 facing the blank area 21 can also be tilted, and the inner end surface surrounded by the edges of the inner end of the high temperature resistant layer 3 facing the blank area 21 is tilted to the end surface of the electrode group 2. The inner end surfaces surrounded by adjacent high temperature resistant layers 3 can be parallel or non-parallel. Figures 1 to 9 As shown, in some embodiments, the battery cell includes a blade battery, and the positive output electrode 5 and the negative output electrode 6 of the blade battery are respectively arranged at the two ends of the housing 1 in the y direction. The blade battery is relatively long, and the high temperature resistant layer 3 is arranged at intervals along the length direction of the blade battery. The blank area 21 and the pressure relief structure 4 are arranged in the middle position of the length direction of the blade battery, which is conducive to shortening the discharge path of the high temperature eruption when the blade battery is thermally runaway, and improving the pressure relief effect of the blade battery. At the same time, the blank area 21 extends along the width direction of the blade battery, which is conducive to shortening the fuse length of the blade battery electrode group 2 and ensuring the fuse effect of the electrode group 2.

[0059] like Figures 1 to 9 As shown, in this embodiment, the high temperature resistant layer 3 is wrapped outside the four sides of the pole group 2, and the end surfaces of the pole group 2 at both ends in the length direction (y direction) are not wrapped with the high temperature resistant layer 3. The two ends of the shell 1 in the length direction are open, and a cover plate is provided on the opening, and the positive output pole 5 and the negative output pole 6 are respectively arranged on the cover plates at both ends. The cover plate is welded to the shell 1. The shell 1 includes an aluminum shell, and the strength of the shell 1 is high. The welding strength between the shell 1 and the cover plate is high, and the high temperature eruption cannot be ejected from the direction of the cover plate. The strength of the pressure relief structure 4 is relatively weak. When the battery cell is thermally runaway, the high temperature and high pressure eruption inside the shell 1 moves toward the pressure relief structure 4. The end surfaces of the pole group 2 at both ends in the length direction are not wrapped with the high temperature resistant layer 3, which can also ensure that the high temperature and high pressure gas moves to the blank area 21 according to the preset path, ensuring the fusing effect of the pole group 2 while saving high temperature resistant materials.

[0060] In some embodiments, the pressure relief structure 4 is centrally arranged along the thickness direction (x direction) of the shell 1, which is beneficial to ensure the uniformity of the exhaust path of high-temperature and high-pressure eruptions at various locations inside the electrode group 2 and improve the exhaust efficiency of the battery cell during thermal runaway.

[0061] Optionally, the pressure relief structure 4 includes an explosion-proof valve. A mounting hole is provided on the housing 1, and the explosion-proof valve is mounted in the mounting hole.

[0062] The positive output electrode 5 includes a positive electrode column, and the negative output electrode 6 includes a negative electrode column. The positive electrode column is arranged on one side cover plate, and the negative electrode column is arranged on the other side cover plate.

[0063] In other embodiments, Fig.10 As shown, the battery cell comprises a square shell battery, the positive pole and the negative pole are arranged on the top of the square shell battery, and the blank area 21 is located between the positive pole and the negative pole. Pressure relief structures 4 are respectively arranged at the top and bottom relative positions of the shell 1.

[0064] In some embodiments, the material of the high temperature resistant layer 3 includes a high temperature resistant insulating material. The high temperature resistant layer 3 has the dual effects of high temperature resistance and insulation. While the high temperature resistance ensures that the high temperature and high pressure eruption materials move in a directional manner into the blank area 21, it can play a good insulating role between the pole group 2 and the shell 1.

[0065] In some embodiments, the melting point difference between the high temperature resistant layer 3 and the blank area 21 is 400°C-1000°C. The large difference in melting points between the two areas ensures that the high temperature resistant layer can protect and fix the electrode group inside it and ensure that the electrode group does not break in the blank area.

[0066] For iron-lithium batteries, the melting point of the electrode group is 200℃-500℃, the melting point of the electrode group of ternary batteries is 600℃-800℃, and the melting point of the high-temperature resistant layer is around 1200℃. The high-temperature resistant layer will not be damaged at 1000℃, and can effectively protect and fix the electrode group inside it.

[0067] Optionally, in some embodiments, the high temperature resistant insulating material includes aramid, basalt fiber, etc. When manufacturing the battery cell, firstly, the electrode group 2 is manufactured, after the electrode group 2 is formed, the high temperature resistant layer 3 is wrapped outside the electrode group 2, and then the electrode group 2 is placed in the shell, and the cover plate is connected to the shell 1.

[0068] According to an embodiment of the present invention, on the other hand, a battery pack is provided, comprising the above-mentioned battery cell, wherein a plurality of battery cells are electrically connected.

[0069] In a battery pack of this structure, when one or some of the cells in the battery pack thermally run away, the pressure relief structure 4 opens. The high-temperature eruption materials at various positions in the pole group 2 move to the blank area 21 of the pole group 2, so that the high-temperature eruption materials can move along the preset exhaust path. The high-temperature materials gathered from various places in the pole group 2 to the blank area 21 heat the pole group 2 in the blank area 21. After the temperature of this area rises to above the melting point of the pole group 2, the blank area 21 of the pole group 2 melts, and the pole group 2 breaks, making it impossible for the entire battery pack system to form a closed electrical circuit, effectively avoiding the battery pack from generating a large area of ​​short-circuit current, and greatly improving the safety performance of the battery pack after the cell thermal runaway.

[0070] Although the embodiments of the present invention have been 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 cell, characterized in that: include: case; A pole group, disposed in the housing; At least two sections of high temperature resistant layers are wrapped around the pole group at intervals along the y direction of the pole group; the pole groups between adjacent high temperature resistant layers form a blank area; A pressure relief structure is provided on the shell, and the pressure relief structure is located within the projection range of the blank area on the shell.

2. The battery cell according to claim 1, characterized in that: The pressure relief structure is provided on the shell at least on one side of the two ends of the blank area along the z-direction.

3. The battery cell according to claim 1 or 2, characterized in that: The shell has a long side and a wide side, and the long side of the shell extends along the y direction.

4. The battery cell according to claim 3, characterized in that: The length of the shell is L, L<300mm, the high temperature resistant layer is provided with two sections, the blank area is provided with one section, and the pressure relief structure is provided on the shell corresponding to the blank area.

5. The battery cell according to claim 3, characterized in that: L≥300mm, the high temperature resistant layer is provided with at least three sections, the blank area is provided with at least two sections, and the pressure relief structure is provided on the shell corresponding to each section of the blank area.

6. The battery cell according to claim 5, characterized in that: The wide side of the shell extends along the z-direction, and at least two of the pressure relief structures located on the same side of the two sides of the shell in the z-direction are arranged at equal intervals along the y-direction of the shell.

7. The battery cell according to claim 1 or 2, characterized in that: The distance between the pressure relief structure and the edge of the projection of the high temperature resistant layer on the shell on the side where the pressure relief structure is located is d, and d≤2 mm.

8. The battery cell according to claim 3, characterized in that: The battery cell includes a blade battery, and the positive output pole and the negative output pole of the blade battery are respectively arranged at two ends of the shell in the y direction.

9. The battery cell according to claim 1 or 2, characterized in that: The material of the high temperature resistant layer includes high temperature resistant insulating material; And / or, the melting point difference between the high temperature resistant layer and the blank area is 400°C-1000°C.

10. A battery pack, characterized in that: The invention comprises a plurality of battery cells according to any one of claims 1 to 9, wherein the plurality of battery cells are electrically connected.

Images