Battery cell overheating protection structure

Abstract

The utility model discloses a battery cell overheating protection structure, which comprises a first electrode plate, a second electrode plate and a base, each of the first electrode plate and the second electrode plate comprises a horizontal main body part and at least one connecting part connected to the horizontal main body part, and the connecting part on the first electrode plate and the connecting part on the second electrode plate are oppositely arranged in the base. A separating wall is arranged in the base to separate the connecting part on the first electrode plate from the connecting part on the second electrode plate, the connecting part on the first electrode plate and the connecting part on the second electrode plate are connected through fusible alloy in a welded mode, and the separating wall is located below the fusible alloy. When a single battery cell or module fails, the temperature is transmitted to the fusible alloy through the electrodes, the fusible alloy is fused and shrunk under the help of the auxiliary agent, alloy breakpoint arcing is prevented under the action of the isolation wall, and finally a circuit and a thermal loop are cut off.

Description

Technical Field

[0001] The utility model relates to the field of circuit protection, and particularly relates to a thermal protection structure for battery cells. Background Art

[0002] Currently, in the market, aluminum bars, nickel sheets, copper bars, etc. are mainly used for the electrical connection of battery cells or modules. When a single battery cell or module fails, heat will be conducted through the aluminum bar and transferred to adjacent battery cells, triggering thermal diffusion. Moreover, when a single failure occurs, the battery cell is prone to ejection, and the ejected matter contains conductive substances, which is likely to cause local short circuits, forming a discharge path, continuously discharging the single failed battery cell or module, and making the failed battery cell or module burn more violently, with the temperature reaching over 1200°C. Therefore, it is necessary to design a structure with over-temperature protection function to protect the circuit. Summary of the Utility Model

[0003] Aiming at the deficiencies of the prior art, the utility model provides a thermal protection structure for battery cells, which has the function of over-temperature protection and can also avoid arcing between the breakpoints of the fusible alloy.

[0004] To achieve the above object, the utility model is realized through the following technical solutions:

[0005] A thermal protection structure for battery cells includes a first electrode plate, a second electrode plate and a base. The first electrode plate and the second electrode plate both include a horizontal main body portion and at least one connecting portion connected to the horizontal main body portion. The connecting portions on the first electrode plate and the connecting portions on the second electrode plate are oppositely arranged in the base. An isolation wall is provided in the base to separate the connecting portions on the first electrode plate and the connecting portions on the second electrode plate. The connecting portions on the first electrode plate and the connecting portions on the second electrode plate are connected by welding with a fusible alloy, and the isolation wall is located below the fusible alloy.

[0006] Further, the connecting portions of the first electrode plate and the connecting portions of the second electrode plate both include at least one row of connecting pieces arranged at intervals. The connecting pieces on the first electrode plate and the connecting pieces on the second electrode plate are in one-to-one correspondence, and the two corresponding connecting pieces are connected by welding with a fusible alloy.

[0007] Further, at least one row of first mounting holes and at least one row of second mounting holes are provided inside the base. The first mounting holes and the second mounting holes are in one-to-one correspondence, and an isolation wall is provided between the corresponding first mounting holes and second mounting holes;

[0008] The number of the first mounting holes is the same as the number of the connecting pieces on the first electrode plate. The first mounting holes in the same row are isolated from each other, and the connecting pieces of the first electrode plate are placed in the corresponding first mounting holes;

[0009] The number of the second mounting holes is the same as the number of the connecting pieces on the second electrode plate. The second mounting holes located in the same row are isolated from each other, and the connecting pieces of the second electrode plate are placed in the corresponding second mounting holes.

[0010] Furthermore, the number of the fusible alloys is the same as the number of the connecting pieces on the first electrode plate and is the same as the number of the connecting pieces on the second electrode plate, and the three are in one-to-one correspondence.

[0011] Furthermore, a chamfer that is beneficial to increasing the contact area between the connecting piece and the fusible alloy is provided on one side of each connecting piece close to the partition wall.

[0012] Furthermore, the first electrode plate includes a first aluminum row and a first copper row. The first aluminum row and the first copper row are lap-welded. The first copper row includes a horizontal part and a connecting part. The horizontal part of the first copper row and the first aluminum row are lap-welded to form the horizontal main body part of the first electrode plate;

[0013] The second electrode plate includes a second aluminum row and a second copper row. The second aluminum row and the second copper row are lap-welded. The second copper row includes a horizontal part and a connecting part. The horizontal part of the second copper row and the second aluminum row are lap-welded to form the horizontal main body part of the second electrode plate.

[0014] Furthermore, the first aluminum row is located above the first copper row. The first electrode is provided with a first through hole for the battery core to contact the first aluminum row. The second aluminum row is located above the second copper row. The second electrode is provided with a second through hole for the battery core to contact the second aluminum row.

[0015] Furthermore, the first copper row and the second copper row are respectively provided with at least two positioning posts, and the first aluminum row and the second aluminum row are respectively provided with at least two positioning holes. Through the cooperation of the positioning posts and the positioning holes, the positioning of the first aluminum row and the first copper row and the positioning of the second aluminum row and the second copper row are realized.

[0016] Furthermore, the base is configured with a cover plate, and a partition wall is provided on the cover plate.

[0017] Furthermore, the cover plate is provided with buckles at least at both ends in the length direction, and the housing is provided with clamping grooves at least at both ends in the length direction for matching with the buckles on the cover plate.

[0018] The utility model has the following beneficial effects:

[0019] 1. When the overheat protection copper row of the battery core works and a single battery core or a module fails, resulting in abnormal temperature rise and discharge of the battery core electrode and further thermal runaway, the temperature is transmitted to the fusible alloy through the electrode. The fusible alloy fuses and shrinks with the help of the auxiliary agent, and the partition wall prevents the alloy break point from arcing. Finally, the circuit and the thermal circuit are cut off, the faulty battery core is removed, and other battery cores are prevented from being affected, so as to finally protect the module.

[0020] 2. The electrode adopts a multi-layer structure of copper busbars stacked and welded to aluminum busbars, which can be directly welded to the battery cell for easy operation.

[0021] 3. A chamfer is provided on one side of the connecting piece close to the partition wall. The inclined plane formed by the chamfer contacts the fusible alloy, thereby increasing the contact area between the connecting piece and the fusible alloy. Increasing the contact area is beneficial for transferring heat to the fusible alloy, improving the breaking capacity, enhancing the feasibility of welding, and also increasing the shrinkage area of the fusible alloy.

[0022] 4. It has an over-temperature protection function, a short-circuit current overload protection function, and the convenience of welding to the battery cell. Description of the Drawings

[0023] Figure 1 is a three-dimensional schematic diagram of the battery cell overheat protection structure of Embodiment 1;

[0024] Figure 2 is Figure 1 another perspective view of the battery cell overheat protection structure of

[0025] Figure 3 is Figure 1 exploded view of the battery cell overheat protection structure of

[0026] Figure 4 is a schematic diagram of the cover plate of Embodiment 1;

[0027] Figure 5 is an assembly diagram of the first electrode and the second electrode with the base;

[0028] Figure 6 is Figure 5 schematic diagram of the fusible alloy welded on the basis of

[0029] Figure 7 is a three-dimensional schematic diagram of the battery cell overheat protection structure of Embodiment 2;

[0030] Figure 8 is Figure 7 view of the battery cell overheat protection structure of Embodiment 2 after removing the cover plate;

[0031] Figure 9 is a schematic diagram of the fusible alloy of the battery cell overheat protection structure of Embodiment 2 after melting;

[0032] Figure 10 is Figure 7 exploded view of the battery cell overheat protection structure of

[0033] Figure 11 is a schematic diagram of the cover plate of Embodiment 2. Detailed Implementation Modes

[0034] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0035] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0036] As Figures 1 to 6 shown, this embodiment discloses a battery cell overheat protection structure, which includes a first electrode sheet, a second electrode sheet, and a base 3. Both the first electrode sheet and the second electrode sheet include a horizontal main body portion and at least one connecting portion 7 connected to the horizontal main body portion. The connecting portions 7 on the first electrode sheet and the connecting portions 7 on the second electrode sheet are both relatively arranged in the base 3. An isolation wall 4 is provided in the base 3 to separate the connecting portions 7 on the first electrode sheet and the connecting portions 7 on the second electrode sheet. The connecting portions 7 on the first electrode sheet and the connecting portions 7 on the second electrode sheet are welded and connected by a fusible alloy 5, and the isolation wall 4 is located below the fusible alloy 5. When this battery cell overheat protection structure works, when a single battery cell or module fails, resulting in abnormal temperature rise and discharge of the battery cell electrodes, and further thermal runaway occurs, the temperature is transmitted to the fusible alloy 5 through the electrodes. The fusible alloy 5 melts and shrinks with the help of a fuse-aid agent. Under the action of the isolation wall 4, the alloy break point is prevented from arcing, and finally the circuit and the thermal circuit are cut off, removing the faulty battery cell and preventing it from affecting other battery cells, ultimately achieving the protection of the module. In some existing overheat protection structures, after the fusible alloy 5 between the electrodes melts, an arc will form between the alloy break points. This solution designs an isolation wall to avoid this phenomenon.

[0037] In this embodiment, the connecting portion 7 is vertical (that is, perpendicular to the base), and the connecting portion 7 occupies a small planar dimension in the base 3. Therefore, the base 3 can be designed with a smaller width, and there is enough space between the connecting portion 7 on the first electrode sheet and the connecting portion 7 on the second electrode sheet to accommodate the fusible alloy 5, and there is enough distance between the connecting portion 7 on the first electrode sheet and the connecting portion 7 on the second electrode sheet to avoid generating an arc.

[0038] In this embodiment, each of the first electrode sheet and the second electrode sheet is provided with a connecting portion 7. The connecting portion 7 of the first electrode sheet and the connecting portion 7 of the second electrode sheet each include at least one row of connecting pieces 9 arranged at intervals. The connecting pieces 9 on the first electrode sheet and the connecting pieces 9 on the second electrode sheet are in one-to-one correspondence, and the two corresponding connecting pieces 9 are welded and connected by a fusible alloy 5.

[0039] Inside the base, there are at least one row of first mounting holes 8 and at least one row of second mounting holes 6. The first mounting holes 8 and the second mounting holes 6 correspond to each other one by one. There is a partition wall between the corresponding first mounting hole 8 and the second mounting hole 6. The number of the first mounting holes 8 is the same as the number of the connecting pieces 9 on the first electrode plate. The first mounting holes 8 in the same row are isolated from each other (separated by the hole walls). The connecting piece 9 of the first electrode plate is placed in the corresponding first mounting hole 8. The number of the second mounting holes 6 is the same as the number of the connecting pieces 9 on the second electrode plate. The second mounting holes 6 in the same row are isolated from each other. The connecting piece 9 of the second electrode plate is placed in the corresponding second mounting hole 6. Both the first mounting holes 8 and the second mounting holes 6 are through holes. In this embodiment, setting the connecting part 7 as multiple connecting pieces 9 helps to improve the current-carrying capacity. In other embodiments, the connecting part 7 can also adopt other shapes. For example, the connecting part 7 can also be a one-piece type with multiple through holes provided thereon.

[0040] Preferably, the number of the fusible alloys 5 is the same as the number of the connecting pieces 9 on the first electrode plate and is the same as the number of the connecting pieces 9 on the second electrode plate. The three correspond to each other one by one. That is to say, the first electrode plate and the second electrode plate are welded by multiple fusible alloys 5. Compared with using a whole fusible alloy to connect the two electrode plates, using multiple fusible alloys 5, the volume of a single fusible alloy is smaller, which is beneficial to accelerating the shrinkage speed of the fusible alloy 5 and is beneficial to quickly extinguishing the arc during breaking.

[0041] In this embodiment, both the first electrode plate and the second electrode plate are provided with four connecting pieces 9. The four connecting pieces 9 on the first electrode plate are spaced apart and arranged in a row. The four connecting pieces 9 on the second electrode plate are spaced apart and arranged in a row. Correspondingly, there is a row of first mounting holes 8 and a row of second mounting holes 6 on the base. A total of four partition walls 4 and four fusible alloys 5 arranged in a column are provided on the base. Each fusible alloy is provided with a fuse-aid agent.

[0042] The first electrode plate includes a first aluminum row 10 and a first copper row 1. The first aluminum row 10 and the first copper row 1 are stacked and welded. The first copper row 1 includes a horizontal part and a vertical part. The vertical part is the connecting part 7. The horizontal part of the first copper row 1 and the first aluminum row 10 are stacked and welded to form the horizontal main body part of the first electrode plate. The second electrode plate includes a second aluminum row 11 and a second copper row 2. The second aluminum row 11 and the second copper row 2 are stacked and welded. The second copper row 2 includes a horizontal part and a vertical part. The vertical part is the connecting part 7. The horizontal part of the second copper row 2 and the second aluminum row 11 are stacked and welded to form the horizontal main body part of the second electrode plate. In some other embodiments, the connecting part 7 is the horizontal part, and the connecting part 7 of the first copper row 1 and the connecting part 7 of the second copper row 2 are arranged horizontally opposite to each other, which is not limited here.

[0043] In this embodiment, the connecting portion 7 on the copper bar is integrally formed with the horizontal portion. The first copper bar 1 and the second copper bar 2 are bent to form an L shape. Through bending, the connecting portion 7 is vertical, and the planar dimension occupied by the connecting portion 7 in the base 3 is small, so the base 3 can be designed with a smaller width. In other embodiments, the connecting portion 7 of the copper bar and the horizontal portion can also be separately formed and then welded. The first electrode plate and the second electrode plate are welded by the fusible alloy 5 after being inserted into the base 3, so that the first electrode plate and the second electrode plate are fixed. The first electrode plate and the second electrode plate can also be directly injection-molded with the base 3 by an in-molding method.

[0044] As an improvement, a chamfer 18 is provided on one side of each connecting piece 9 close to the partition wall 4. The inclined surface formed by the chamfer contacts the fusible alloy 5. Each inclined surface is a welding point, thereby increasing the contact area between the connecting piece 9 and the fusible alloy 5. Increasing the contact area is beneficial to transferring heat to the fusible alloy 5, improving the breaking capacity, enhancing the feasibility of welding, and also increasing the shrinkage area of the fusible alloy 5.

[0045] Whether it is a copper bar or an aluminum bar, it can be welded to the battery cell and the fusible alloy 5. Considering that it is not easy to weld the fusible alloy 5 to the aluminum bar, but the fusible alloy 5 is easy to weld to the copper bar, and it is not easy to weld the copper bar to the battery cell, while the aluminum bar is easy to weld to the battery cell. Therefore, in this solution, a copper bar is stacked and welded to an aluminum bar as the electrode.

[0046] Specifically, the first aluminum bar 10 is located above the first electrode plate. The first electrode plate is provided with a first through hole 12 for the battery cell to contact the first aluminum bar 10. The second aluminum bar 11 is located above the second electrode plate. The second electrode plate is provided with a second through hole 13 for the battery cell to contact the second aluminum bar 11. In other embodiments, it is not excluded that the aluminum bar can be stacked and welded below the copper bar, or the aluminum bar is welded to one end of the copper bar, the copper bar is welded to the fusible alloy, and the aluminum bar is welded to the battery cell.

[0047] In this embodiment, the first copper bar 1 and the second copper bar 2 are respectively provided with at least two positioning posts 14, and the first aluminum bar 10 and the second aluminum bar 11 are respectively provided with at least two positioning holes 15. Through the cooperation of the positioning posts 14 and the positioning holes 15, the positioning of the first aluminum bar 10 and the first copper bar 1, and the positioning of the second aluminum bar 11 and the second copper bar 2 are realized.

[0048] The base is square. The base 3 is configured with a cover plate 16, and an isolation wall is provided on the cover plate to further optimize the arc extinguishing effect. Glue is applied to the top surface of the base 3, and the cover plate 16 and the base 3 are adhesively bonded with glue and then fastened by a buckle 17. Specifically, the cover plate 16 is provided with buckles 17 at least at both ends in the length direction, and the base 3 is provided with slots 19 at least at both ends in the length direction for matching with the buckles 17 on the cover plate 16. A glue application position is designed on the base 3, and the buckle 17 position is designed on the cover plate 16. After being fastened, it can be directly cured to prevent the cover plate 16 from shifting during the curing process. The base 3 and the cover plate 16 can also be connected in other ways, such as welding. A sealing ring can be used for sealing between the base 3 and the cover plate 16, and the base 3 and the cover plate 16 can be locked by screws.

[0049] The overheat protection structure of the battery cell provided in this embodiment has an over-temperature protection function and a short-circuit current overload protection function, and at the same time has convenience in welding with the battery cell. It is installed between battery cells. When a battery cell undergoes thermal runaway, it causes abnormal temperature rise and discharge of the battery cell electrodes, and further before thermal runaway occurs. By melting itself, the circuit and temperature loop are cut off, and the risky battery cell is removed from the battery module to prevent further thermal runaway. Thus, the entire power battery system is protected. The protection principle is as follows:

[0050] The ambient temperature is transferred to the first aluminum row 10 and the second aluminum row 11, then the temperature is transferred to the first copper row 1 and the second copper row 2, and then transferred to the fusible alloy. The fusible alloy 5 melts and shrinks with the help of a fuse-aid agent to cut off the circuit and thermal loop.

[0051] Embodiment 2

[0052] The overheat protection structure of the battery cell in this embodiment is substantially the same as the structure in Embodiment 1, such as Figures 7 to 11 , the difference is that:

[0053] The connecting part 7 of the first copper row 1 is provided with two, and each connecting part 7 is provided with a row of connecting pieces 9, and the two rows of connecting pieces 9 are arranged in a staggered manner. Correspondingly, the connecting part 7 of the second copper row 2 is also provided with two, and each connecting part 7 is provided with a row of connecting pieces 9, and the two rows of connecting pieces 9 are arranged in a staggered manner.

[0054] The connecting pieces 9 on the first copper bar 1 and the connecting pieces 9 on the second copper bar 2 are connected in one-to-one correspondence through a fusible alloy 5. The base 3 is adaptively changed according to the structure of the copper bar. Specifically, the base 3 includes two mounting parts 31 and a bridging section 32 connecting the two mounting parts 31. The two rows of connecting pieces 9 of the first copper bar 1 are respectively placed in the two mounting parts 31 of the base, and the two rows of connecting pieces 9 of the second copper bar 2 are respectively placed in the two mounting parts 31 of the base. Each mounting part 31 is provided with a row of first mounting holes 8 and a row of second mounting holes 6. The first mounting holes 8 and the second mounting holes 6 are in one-to-one correspondence and are separated by a partition wall. The connecting piece 9 on the first copper bar 1 is inserted into the first mounting hole 8, and the connecting piece 9 on the second copper bar 2 is inserted into the second mounting hole 6.

[0055] In the embodiment, there are two cover plates. The structure of the cover plate 16 is adapted to the structure of the base, and the cover plate 16 is provided with a partition wall to enhance the arc extinguishing ability; the cover plate 16 is provided with a buckle 17, which cooperates with a corresponding slot 19 provided on the base.

[0056] For the parts of the overheat protection structure of the battery cell in this embodiment that do not conflict with those in the first embodiment, the design of the first embodiment can be adopted.

[0057] As described above, the embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Therefore, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Claims

1. A battery cell overheat protection structure, characterized in that: It includes a first electrode sheet, a second electrode sheet and a base, the first electrode sheet and the second electrode sheet both include a horizontal main body and at least one connecting portion connected to the horizontal main body, the connecting portion on the first electrode sheet and the connecting portion on the second electrode sheet are relatively arranged in the base, an isolation wall is provided in the base to separate the connecting portion on the first electrode sheet and the connecting portion on the second electrode sheet, the connecting portion on the first electrode sheet and the connecting portion on the second electrode sheet are connected by welding with a fusible alloy, and the isolation wall is located below the fusible alloy.

2. The battery core overheat protection structure according to claim 1, characterized in that: The connecting portion of the first electrode sheet and the connecting portion of the second electrode sheet both include at least one row of connecting sheets spaced apart from each other. The connecting sheets on the first electrode sheet are opposite to the connecting sheets on the second electrode sheet, and the two opposite connecting sheets are connected by welding with fusible alloy.

3. The battery core overheat protection structure according to claim 2, characterized in that: At least one row of first mounting holes and at least one row of second mounting holes are provided inside the base, the first mounting holes and the second mounting holes correspond to each other one by one, and a separation wall is provided between the corresponding first mounting holes and the second mounting holes; The number of the first mounting holes is the same as the number of the connecting plates on the first electrode sheet, the first mounting holes in the same row are isolated from each other, and the connecting plates of the first electrode sheet are placed in the corresponding first mounting holes; The number of the second mounting holes is the same as the number of the connecting plates on the second electrode plate. The second mounting holes in the same row are isolated from each other, and the connecting plates of the second electrode plate are placed in the corresponding second mounting holes.

4. The battery core overheat protection structure according to claim 2 or 3, characterized in that: The number of the fusible alloy is the same as the number of the connecting plates on the first electrode plate, and is the same as the number of the connecting plates on the second electrode plate, and the three correspond one to one.

5. The battery core overheat protection structure according to claim 2, characterized in that: Each connecting piece is provided with a chamfer on one side close to the isolation wall, which is beneficial to increasing the contact area between the connecting piece and the fusible alloy.

6. The battery core overheat protection structure according to claim 1, characterized in that: The first electrode sheet includes a first aluminum bar and a first copper bar, the first aluminum bar and the first copper bar are welded together, the first copper bar includes a horizontal portion and a connecting portion, and the horizontal portion of the first copper bar and the first aluminum bar are welded together to form a horizontal main body of the first electrode sheet; The second electrode sheet includes a second aluminum bar and a second copper bar, the second aluminum bar and the second copper bar are welded together, the second copper bar includes a horizontal portion and a connecting portion, and the horizontal portion of the second copper bar and the second aluminum bar are welded together to form a horizontal main body of the second electrode sheet.

7. The battery core overheat protection structure according to claim 6, characterized in that: The first aluminum row is located above the first copper row, the first electrode is provided with a first through-hole power supply core in contact with the first aluminum row, the second aluminum row is located above the second copper row, the second electrode is provided with a second through-hole power supply core in contact with the second aluminum row.

8. The battery core overheat protection structure according to claim 7, characterized in that: The first copper bar and the second copper bar are respectively provided with at least two positioning columns, and the first aluminum bar and the second aluminum bar are respectively provided with at least two positioning holes. The positioning of the first aluminum bar and the first copper bar, as well as the positioning of the second aluminum bar and the second copper bar are achieved through the cooperation of the positioning columns and the positioning holes.

9. The battery core overheat protection structure according to claim 1, characterized in that: The base is provided with a cover plate, and a separation wall is arranged on the cover plate.

10. The battery core overheat protection structure according to claim 9, characterized in that: The cover plate is provided with buckles at least at two ends in the length direction, and the shell is provided with slots at least at two ends in the length direction for matching with the buckles on the cover plate.

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