Battery cell, battery module and battery pack

Abstract

The utility model relates to a battery cell, a battery module and a battery pack. The battery core comprises a shell and an isolating membrane covering the surface of the shell, a pressure relief part is arranged on the first end face of the shell, and when the pressure or temperature in the battery exceeds a set value, the anti-explosion valve is instantly directly communicated with the outside, so that the pressure in the battery is quickly reduced, and explosion accidents are avoided. The isolating membrane comprises a side surface section and an end surface section which are split, and when the battery cell is assembled, the side surface section is coated on the first side surface of the shell, and the end surface section is coated on the first end surface of the shell, so that split bonding is realized. As the end surface section and the side surface section are designed in a split manner, the first window on the end surface section can be conveniently aligned with the pressure relief part, the alignment difficulty of the pressure relief part and the first window of the isolating membrane is reduced, the pressure relief reliability of the pressure relief part and the insulation effect of the battery cell are ensured, the membrane pasting difficulty of the isolating membrane is reduced, and the production efficiency is improved. Therefore, unnecessary loss of the isolating membrane is reduced, and the use cost of the isolating membrane is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to battery cells, battery modules and battery packs. Background Art

[0002] The new energy battery explosion-proof valve is a safety valve used in battery modules or energy storage devices. Its main function is to monitor the pressure and temperature inside the battery. When the pressure or temperature exceeds the set value, the explosion-proof valve will instantly connect to the outside, allowing a large amount of gas inside the battery to be discharged, thereby quickly releasing the strong pressure inside the cavity to reduce the pressure inside the battery and avoid the occurrence of explosion accidents.

[0003] In existing lithium-ion batteries, in order to ensure the insulation performance between two adjacent battery cells in the battery module, an isolation membrane is usually coated on the outer surface of the battery cell shell to insulate the adjacent battery cells. In order to prevent the pressure when the explosion-proof valve is opened from being insufficient to break the isolation membrane and affect the safety performance of the battery cell, it is necessary to make a hole in the isolation membrane corresponding to the explosion-proof valve. When assembling the battery cell, the hole on the isolation membrane is aligned with the battery cell explosion-proof valve through the alignment equipment. If the hole on the isolation membrane is not aligned with the explosion-proof valve, it is necessary to cut off the isolation membrane in the non-aligned area, thereby increasing the use cost and loss of the isolation membrane. Utility Model Content

[0004] Based on this, it is necessary to provide a battery cell to address the problems of high cost and loss of isolation membranes in existing battery cells.

[0005] A battery cell, comprising:

[0006] A shell, wherein the shell has a plurality of first side surfaces and two first end surfaces, wherein the plurality of first side surfaces are distributed along the circumference of the shell; the two first end surfaces are respectively located at two ends of the shell; and a pressure relief portion is provided on the first end surface;

[0007] The isolation membrane includes a split side segment and an end segment, wherein at least a portion of the side segment is covered on the first side surface; the end segment is covered on the first end surface, and a first window is formed on the end segment, wherein the position of the first window corresponds to the position of the pressure relief portion.

[0008] In one embodiment, the side segment includes a first branch segment and a second branch segment connected to the first branch segment, the first branch segment is wrapped around the first side surface; the second branch segment is provided with a second window so that the second branch segment is wrapped around the first area of ​​the first end surface.

[0009] In one embodiment, the end face segment is covered on a second region of the first end face, and the second region partially overlaps with the first region.

[0010] In one embodiment, the width of the end surface segment is greater than or equal to the width of the second window.

[0011] In one embodiment, the difference between the width of the end face segment and the width of the second window is in the range of 0 mm to 20 mm.

[0012] A battery module comprises a plurality of battery cells as described above, wherein the plurality of battery cells are stacked in sequence to form a battery cell group.

[0013] In one embodiment, the battery module further includes side panels, which are arranged on both sides of the battery cell group.

[0014] In one embodiment, the battery module further includes end plates, and the end plates are disposed at both ends of the battery cell group.

[0015] A battery pack comprises a battery box and the battery module as described above, wherein the battery module is arranged in the battery box.

[0016] In one of the embodiments, the battery box is provided with an exhaust hole, and the exhaust hole is connected to the pressure relief part.

[0017] The above-mentioned battery cell includes a shell and an isolation membrane wrapped on the surface of the shell. A pressure relief portion is provided on the first end face of the shell. In this way, when the pressure or temperature inside the battery exceeds the set value, the explosion-proof valve will instantly communicate with the outside, so that a large amount of gas inside the battery is discharged, thereby quickly releasing the strong pressure inside the cavity to reduce the pressure inside the battery and avoid the occurrence of explosion accidents. The isolation membrane includes a split side segment and an end face segment. When assembling the battery cell, the side segment is wrapped on the first side of the shell, and the end face segment is wrapped on the first end face of the shell to achieve split bonding. Since the end face segment and the side segment are split designs, the first window on the end face segment can be easily aligned with the pressure relief portion, which reduces the difficulty of aligning the pressure relief portion with the first window of the isolation membrane, while ensuring the pressure relief reliability of the pressure relief portion and the insulation effect of the battery cell, reducing the difficulty of sticking the isolation membrane, thereby reducing unnecessary loss of the isolation membrane and reducing the use cost of the isolation membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a battery cell provided in accordance with an embodiment of the present application.

[0019] Figure 2 for Figure 1 An exploded schematic diagram of the battery cell is shown.

[0020] Figure 3 for Figure 2 Schematic diagram of the separator in the battery cell shown.

[0021] Figure 4 for Figure 2 Schematic diagram of the separator in the battery cell shown.

[0022] Figure 5 A schematic diagram of a battery module provided in accordance with an embodiment of the present application.

[0023] Figure numbers: 10, battery module; 100, battery cell; 110, shell; 111, first side surface; 112, first end surface; 120, isolation membrane; 121, side section; 1211, first branch section; 1212, second branch section; 1213, second window; 122, end section; 1221, first window; 130, pressure relief part; 200, side plate; 300, end plate. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0025] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0026] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0028] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0029] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0030] See also Figures 1 to 3 As shown, a battery cell 100 provided in an embodiment of the present application includes a shell 110 and an isolation membrane 120; the shell 110 has a plurality of first side surfaces 111 and two first end surfaces 112, and the plurality of first side surfaces 111 are distributed along the circumference of the shell 110; the two first end surfaces 112 are respectively located at the two ends of the shell 110; the first end surface 112 is provided with a pressure relief portion 130; the isolation membrane 120 includes a split side section 121 and an end surface section 122, and at least a portion of the side section 121 is covered on the first side surface 111; the end surface section 122 is covered on the first end surface 112, and the end surface section 122 is provided with a first window 1221, and the position of the first window 1221 corresponds to the position of the pressure relief portion 130.

[0031] The battery cell 100 is provided with a pressure relief portion 130 on the first end face 112 of the shell 110. Thus, when the pressure or temperature inside the battery exceeds a set value, the explosion-proof valve will instantly communicate with the outside, so that a large amount of gas inside the battery is discharged, thereby quickly releasing the strong pressure inside the cavity to reduce the pressure inside the battery and avoid the occurrence of explosion accidents. The isolation membrane 120 includes a split side segment 121 and an end segment 122. When assembling the battery cell 100, the side segment 121 can be coated on the first side face 111 of the shell 110, and the end segment 122 can be coated on the first end face 112 of the shell 110 to achieve split bonding. Since the end face section 122 and the side face section 121 are split designs, the first window 1221 on the end face section 122 can be easily aligned with the pressure relief section 130, which reduces the difficulty of aligning the pressure relief section 130 with the first window 1221 of the isolation film 120, and while ensuring the pressure relief reliability of the pressure relief section 130 and the insulation effect of the battery cell 100, it reduces the difficulty of sticking the isolation film 120, thereby reducing unnecessary loss of the isolation film 120 and reducing the use cost of the isolation film 120. In addition, by bonding the end face section 122 to the end face of the housing 110, the use of top patches can be reduced, costs can be reduced, and it is easy to improve the current capacity of the battery cell 100, increase the fast charging rate of the battery cell 100, improve the insulation performance of the battery, and have higher safety.

[0032] It can be understood that the isolation film 120 is an insulating material with corrosion resistance and high tensile strength, preferably a polyester film, and the thickness of the isolation film 120 is 0.015mm to 0.20mm. By coating the surface of the shell 110 with a layer of isolation film 120, the surface of the battery cell 100 can be protected, and the adjacent battery cells 100 can be separated from each other to block the impact of a single battery cell 100 on other battery cells 100 due to various faults. The pressure relief part 130 can be specifically an explosion-proof valve. By setting the explosion-proof valve, the explosion-proof valve opens when the air pressure in the shell 110 reaches a preset value, so that the sealed cavity in the shell 110 is connected to the outside world to reduce the air pressure in the sealed cavity, avoid the battery cell 100 from exploding due to excessive pressure and other dangerous situations, and play a role in safety protection.

[0033] See also Figures 2 to 4As shown, in one embodiment, the side segment 121 includes a first branch segment 1211 and a second branch segment 1212 connected to the first branch segment 1211, the first branch segment 1211 is wrapped around the first side surface 111; the second branch segment 1212 is provided with a second window 1213, so that the second branch segment 1212 is wrapped around the first area of ​​the first end surface 112. In other words, the side segment 121 is approximately annular, and when it is wrapped around the first side surface 111 of the shell 110, it also extends a flange, namely the second branch segment 1212, so that the end surface segment 122 can be better spliced ​​with the side segment 121, thereby improving the insulation isolation effect between two adjacent battery cells 100.

[0034] See also Figures 2 to 4 As shown, in one embodiment, the end face segment 122 is coated on the second area of ​​the first end face 112, and the second area partially overlaps with the first area. It can be seen that the second area is located at the edge of the first area, and the second area partially overlaps with the first area, so that the side segment 121 and the end face segment 122 have an overlapping area, thereby ensuring the insulation effect of the isolation film 120 on the battery cell 100.

[0035] See also Figures 2 to 4 As shown, in one embodiment, the width W1 of the end face section 122 is greater than or equal to the width W2 of the second window 1213. The difference between the width W1 of the end face section 122 and the width W2 of the second window 1213 is in the range of 0 mm to 20 mm. In this way, the side face section 121 and the end face section 122 have overlapping bonding areas, thereby ensuring the insulation effect of the isolation film 120 on the battery cell 100.

[0036] Furthermore, if Figure 5 As shown, an embodiment of the present application further provides a battery module 10, comprising a plurality of battery cells 100 as described above, wherein the plurality of battery cells 100 are stacked in sequence to form a battery cell group, and adjacent battery cells 100 are bonded by a first colloid. Since the battery module 10 comprises the battery cells 100 of any of the above embodiments, when assembling the battery cells 100, the first window 1221 on the isolation film 120 can be easily aligned with the pressure relief portion 130 of the housing 110, thereby reducing the difficulty of aligning the pressure relief portion 130 with the first window 1221 of the isolation film 120, ensuring the pressure relief reliability of the pressure relief portion 130 and the insulation effect of the battery cell 100, while reducing the difficulty of attaching the isolation film 120, thereby reducing unnecessary loss of the isolation film 120 and reducing the use cost of the isolation film 120.

[0037] See also Figures 2 to 5As shown, in some embodiments, in order to improve the connection strength between adjacent battery cells 100, a third window (not shown) is opened on the side segment 121 of the isolation film 120, and a first colloid (not shown) is coated on the first side 111 of the battery cell 100 at a position corresponding to the third window, and the first colloid is used to bond with the adjacent battery cell 100. Since the isolation film 120 is relatively smooth, when the first colloid is directly arranged on the isolation film 120 to achieve bonding between two adjacent battery cells 100, the first colloid is easy to fall off, and the two battery cells 100 will be separated after the first colloid falls off, which may cause the battery module 10 to break in severe cases. Therefore, by opening a third window on the isolation film 120 between adjacent battery cells 100 and coating the first colloid on the third window, the first colloid is in contact with the housing 110 of the battery cell 100, but not in contact with the isolation film 120, thereby improving the adhesion between the first colloid and the battery cell 100, thereby improving the connection strength between adjacent battery cells 100, reducing the risk of battery module 10 breakage, and improving the safety performance of the battery module 10. The first colloid may specifically be a structural adhesive, which has high strength, peeling resistance, impact resistance, and simple construction process.

[0038] In some embodiments, a plurality of third windows may be provided, and the plurality of third windows may be arranged along the length direction or the width direction of the battery cell to ensure the bonding effect between adjacent battery cells.

[0039] like Figure 5 As shown, in one embodiment, the battery module 10 further includes side panels 200, and the side panels 200 are disposed on both sides of the battery cell group. Figure 5 As shown, the side plates 200 are arranged on the left and right sides of the battery cell group. By setting the side plates 200, strength is provided to resist the expansion force of the battery module 10. Furthermore, an insulating member is arranged between the side plates 200 and the battery cell 100, and the insulating member can insulate the battery cell 100 from the side plates 200. At the same time, the insulating member also has thermal conductivity, which is conducive to dissipating the heat of the battery cell 100 and improving the heat dissipation capacity of the battery module 10.

[0040] like Figure 5 As shown, in one embodiment, the battery module 10 further includes an end plate 300, and the end plate 300 is disposed at both ends of the battery cell group. The end plate 300 is disposed at the front and rear ends of the battery cell group to further increase the use strength of the battery module 10. Furthermore, an insulating member may be disposed between the battery cell 100 and the end plate 300 to improve the heat dissipation capacity of the battery module 10.

[0041] Furthermore, an embodiment of the present application also provides a battery pack, including a battery box (not shown) and the battery module 10 as described above, wherein the battery module is arranged in the battery box. Since the battery pack includes the battery module of any of the above embodiments, the first window on the isolation membrane can be easily aligned with the pressure relief portion of the housing, which reduces the difficulty of aligning the pressure relief portion with the first window of the isolation membrane, ensures the pressure relief reliability of the pressure relief portion and the insulation effect of the battery cell, and reduces the difficulty of attaching the isolation membrane, thereby reducing unnecessary loss of the isolation membrane and reducing the use cost of the isolation membrane.

[0042] In one embodiment, the battery box is provided with an exhaust hole (not shown), and the exhaust hole is connected to the pressure relief part. In this way, the hot gas generated when the battery cell is in thermal runaway can be discharged from the battery box through the exhaust hole after being discharged through the pressure relief part, preventing the hot gas from being discharged into the battery box, and then separating the hot gas from the electrical appliances inside the battery box to achieve thermal and electrical separation. Among them, the number of exhaust holes and pressure relief parts can be at least two, so that the exhaust speed of the battery module can be effectively improved to ensure the exhaust efficiency when the battery cell is in thermal runaway and improve the safety performance of the battery pack.

[0043] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A battery cell, characterized in that: The battery cell comprises: A shell (110), the shell (110) having a plurality of first side surfaces (111) and two first end surfaces (112), the plurality of first side surfaces (111) being distributed along the circumference of the shell (110); the two first end surfaces (112) being respectively located at two ends of the shell (110); and the first end surface (112) being provided with a pressure relief portion (130); An isolation membrane (120), the isolation membrane (120) comprising a split side segment (121) and an end segment (122), wherein at least a portion of the side segment (121) is covered on the first side surface (111); the end segment (122) is covered on the first end surface (112), and the end segment (122) is provided with a first window (1221), wherein the position of the first window (1221) corresponds to the position of the pressure relief portion (130).

2. The battery cell according to claim 1, characterized in that: The side segment (121) comprises a first branch segment (1211) and a second branch segment (1212) connected to the first branch segment (1211); the first branch segment (1211) is coated on the first side surface (111); the second branch segment (1212) is provided with a second window (1213) so that the second branch segment (1212) is coated on the first area of ​​the first end surface (112).

3. The battery cell according to claim 2, characterized in that: The end surface segment (122) covers a second area of ​​the first end surface (112), and the second area partially overlaps with the first area.

4. The battery cell according to claim 2, characterized in that: The width of the end surface section (122) is greater than or equal to the width of the second window (1213).

5. The battery cell according to claim 4, characterized in that: The difference between the width of the end surface section (122) and the width of the second window (1213) is in the range of 0 mm to 20 mm.

6. A battery module, characterized in that: Comprising a plurality of battery cells (100) according to any one of claims 1 to 5, wherein the plurality of battery cells (100) are stacked in sequence to form a battery cell group.

7. The battery module according to claim 6, characterized in that: The battery module also includes side plates (200), and the side plates (200) are arranged on both sides of the battery cell group.

8. The battery module according to claim 6, characterized in that: The battery module further comprises an end plate (300), wherein the end plate (300) is arranged at two ends of the battery cell group.

9. A battery pack, characterized in that: It comprises a battery box and a battery module as claimed in any one of claims 6 to 8, wherein the battery module is arranged in the battery box.

10. The battery pack according to claim 9, characterized in that: The battery box is provided with an exhaust hole, and the exhaust hole is connected to the pressure relief part.

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