Electrical core internal insulating film and electrical core
By setting air guide grooves on the internal insulating film of the battery cell, the problem of the explosion-proof valve being blocked by components such as the electrode assembly is solved, enabling the normal opening and pressure relief of the explosion-proof valve and improving the energy density of the battery cell.
Patent Information
- Application Number
- CN202511112149.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-08
- Publication Date
- 2025-12-12
AI Technical Summary
Components such as the electrode assembly inside the battery cell can easily clog the explosion-proof valve, preventing the internal air pressure from acting on the valve. Even if the air pressure exceeds the explosion-proof valve's threshold, the valve cannot open properly to release pressure.
An air guide groove is set on the insulating film inside the battery cell, which is connected to the gap between the battery cell shell and the insulating film body. This ensures that the pressure inside the explosion-proof valve is consistent with the pressure in other parts of the battery cell. The air guide groove does not increase the internal space of the battery cell, so that the explosion-proof valve can open normally to release pressure when the pressure exceeds the threshold.
This effectively solves the problem of components such as electrode groups clogging the explosion-proof valve, ensuring that the explosion-proof valve can open normally to release pressure, reducing the size of the battery cell and increasing the energy density of the battery cell.
Smart Images
Figure CN121123584A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery cell structure technology, and more particularly to an internal insulating film and a battery cell. Background Technology
[0002] In related technologies, battery cell casings are typically equipped with explosion-proof valves. When thermal runaway occurs inside the cell and the internal pressure exceeds a threshold, the explosion-proof valve opens to release the high-pressure gas inside the cell, preventing further increases in temperature and pressure that could lead to a safety accident. However, to reduce the size of the battery cell and increase its energy density, the internal space of the cell is usually reduced. This results in insufficient space between the internal components such as the electrode assembly and the inner wall of the cell casing. Consequently, these components can easily clog the explosion-proof valve, preventing the internal pressure from acting on it. Even if the pressure exceeds the explosion-proof valve's threshold, the valve may not open properly to release pressure. Summary of the Invention
[0003] This invention provides an internal insulating film and a battery cell to solve the defects in the prior art where the electrode group and other components inside the battery cell easily clog the explosion-proof valve, causing the internal air pressure of the battery to be unable to act on the explosion-proof valve, and even if the air pressure exceeds the threshold of the explosion-proof valve, the explosion-proof valve cannot open normally to release pressure.
[0004] In a first aspect, the present invention provides an internal insulating film for a battery cell, comprising: An insulating film body is configured to be disposed between a battery cell housing and an electrode assembly to isolate the battery cell housing and the electrode assembly; the insulating film body has an air guide groove on the side facing the explosion-proof valve, at least a portion of the air guide groove is disposed opposite to the explosion-proof valve, and the air guide groove communicates with the gap between the battery cell housing and the insulating film body.
[0005] According to the internal insulating film of the battery cell of the present invention, the insulating film body includes a first part, a second part and a third part connected together, the first part covering a first side of the electrode group, the second part covering a second side of the electrode group, and the third part covering a third side of the electrode group; the first side of the electrode group is the side of the electrode group facing the explosion-proof valve, the second side is the side adjacent to the first side, and the third side is the side opposite to the first side; The air guide groove is disposed in the first part; or, the air guide groove extends from the first part to the second part; or, the air guide groove extends from the first part to the second part and the third part in sequence.
[0006] According to the internal insulating film of the battery cell of the present invention, there are at least two second portions; the two second portions are arranged opposite to each other, and the third portion is connected to at least one of the second portions.
[0007] According to the internal insulating film of the battery cell of the present invention, the third part and the second part are connected in a one-to-one correspondence, and at least a portion of the two third parts are stacked on top of each other.
[0008] According to the internal insulating film of the battery cell of the present invention, the width of the electrode group is A, the length is B, the dimension of the air guide groove along the width direction of the electrode group is a, and the dimension of the air guide groove along the length direction of the electrode group is b; When the air guide groove is only provided in the first part, a satisfies: a≥0.1A; b satisfies: b≥0.1B.
[0009] According to the internal insulating film of the battery cell of the present invention, the air guide groove includes a first groove and a plurality of second grooves; The first groove extends along the length direction of the electrode group, the second groove extends along the width direction of the electrode group, the middle part of the second groove is connected to the first groove, and a plurality of second grooves are arranged at intervals along the extension direction of the first groove.
[0010] According to the internal insulating film of the battery cell of the present invention, the width of both the first groove and the second groove is not less than 0.01 mm.
[0011] According to the present invention, the thickness of the insulating film body is H, and the depth of the air guide groove is h, wherein h satisfies: 0.001H≤h≤0.99H.
[0012] According to the present invention, the internal insulating film of the battery cell is a PP film, PI film, PE film or PET film.
[0013] In a second aspect, the present invention provides a battery cell, comprising: a battery cell housing, an electrode assembly, and an internal insulating film of the battery cell as described in any one of the above claims; The battery cell housing is provided with an exhaust port, and the exhaust port is equipped with an explosion-proof valve; the insulating film body and the electrode assembly are disposed in the inner cavity of the battery cell housing, and the insulating film body covers the electrode assembly.
[0014] The internal insulating film of the present invention features an air guide groove on its body, positioned opposite the explosion-proof valve of the cell housing. This air guide groove maintains communication with the gap between the cell housing and the insulating film body at other locations within the cell, ensuring that the pressure inside the explosion-proof valve remains consistent with the pressure at other locations within the cell. This allows the explosion-proof valve to open normally and release pressure when the internal pressure rises and exceeds its threshold. Furthermore, since the air guide groove is located on the surface of the insulating film body, it eliminates the need for additional space between the cell housing and the insulating film body, thus reducing the internal space of the cell and consequently decreasing its volume. This improves the cell's energy density and effectively solves the problem in the prior art where components such as the electrode assembly inside the cell easily clog the explosion-proof valve, preventing the internal air pressure from acting on it, and even when the air pressure exceeds the explosion-proof valve's threshold, the valve cannot open normally to release pressure. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0016] Figure 1 This is a schematic diagram of the insulating film body provided in an embodiment of the present invention.
[0017] Figure 2 This is a schematic diagram of the battery cell provided in an embodiment of the present invention.
[0018] Figure 3 This is a cross-sectional view of the battery cell provided in an embodiment of the present invention.
[0019] Figure label: 1. Insulating film body; 11. Air guide groove; 111. First groove; 112. Second groove; 12. First part; 13. Second part; 14. Third part; 2. Cell casing; 3. Electrode assembly. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0021] The following is combined Figures 1-3 The internal insulating film of the battery cell of the present invention is described.
[0022] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides an internal insulating film for a battery cell, comprising: an insulating film body 1, which is configured to be disposed between a battery cell housing 2 and an electrode assembly 3 for isolating the battery cell housing 2 and the electrode assembly 3. An air guide groove 11 is constructed on the side of the insulating film body 1 facing an explosion-proof valve (not shown in the figure), at least a portion of which is disposed opposite to the explosion-proof valve, and the air guide groove 11 communicates with the gap between the battery cell housing 2 and the insulating film body 1.
[0023] In this embodiment, it is understood that the insulating film body 1 is used to wrap around the outside of components such as the electrolyte and electrode assembly 3 to prevent these components from directly contacting the cell housing 2 and forming a short circuit. An explosion-proof valve for venting and depressurizing is provided on one side of the cell housing 2. A venting groove 11 is provided on the outside of the insulating film body 1 corresponding to the position of the explosion-proof valve. At least a portion of the venting groove 11 is positioned opposite to the explosion-proof valve, thus ensuring that a certain space is always maintained between the inner side of the explosion-proof valve and the insulating film body 1. This space is connected to the gap between the cell housing 2 and the insulating film body 1 through the venting groove 11, ensuring that the gas pressure in this space is consistent with the gas pressure in other locations within the cell housing 2. When the inside of the cell overheats, causing the gas to expand and increase in pressure, the gas in the space inside the explosion-proof valve can also increase in pressure synchronously, allowing the explosion-proof valve to open normally to vent and depressurize when the internal gas pressure exceeds a threshold.
[0024] The internal insulating film of the present invention features an air guide groove 11 on the insulating film body 1, positioned opposite the explosion-proof valve of the cell housing 2. This air guide groove 11 maintains communication with the gap between the cell housing 2 and the insulating film body 1 at other locations within the cell, ensuring that the pressure inside the explosion-proof valve remains consistent with the pressure at other locations within the cell. This allows the explosion-proof valve to open normally and release pressure when the internal pressure rises and exceeds the explosion-proof valve threshold. Furthermore, since the air guide groove 11 is located on the surface of the insulating film body 1, it eliminates the need for additional space between the cell housing 2 and the insulating film body 1, reducing the internal space of the cell and thus decreasing its volume. This, in turn, increases the cell's energy density. The invention effectively solves the problem in the prior art where components such as the electrode assembly inside the cell easily clog the explosion-proof valve, preventing the internal air pressure from acting on it, and even when the air pressure exceeds the explosion-proof valve threshold, the valve cannot open normally to release pressure.
[0025] In some embodiments, such as Figure 1 and Figure 3As shown, the insulating film body 1 includes a first part 12, a second part 13, and a third part 14 connected together. The first part 12 covers a first side of the electrode group 3, the second part 13 covers a second side of the electrode group 3, and the third part 14 covers a third side of the electrode group 3. The first side of the electrode group 3 is the side facing the explosion-proof valve, the second side is the adjacent side of the first side, and the third side is the opposite side of the first side. A gas guide groove 11 is disposed in the first part 12. Alternatively, the gas guide groove 11 extends from the first part 12 to the second part 13. Alternatively, the gas guide groove 11 extends sequentially from the first part 12 to the second part 13 and the third part 14.
[0026] It is understood that the electrode assembly 3 typically has multiple sides. For example, the electrode assembly 3 is typically rectangular in shape. The first and third sides of the electrode assembly 3 are opposite sides, with the first side facing the explosion-proof valve and the third side facing away from the explosion-proof valve. The second side is the side that is connected to both the first and third sides. The insulating film body 1 of this embodiment includes a first part 12, a second part 13, and a third part 14. The first part 12 is disposed corresponding to the first side, the second part 13 is disposed corresponding to the second side, and the third part 14 is disposed corresponding to the third side, so as to provide insulation between the electrode assembly 3 and the cell housing 2.
[0027] Optionally, the air guide groove 11 can be provided only in the first part 12, so that the gas between other positions of the insulating film body 1 and the battery cell housing 2 can be introduced into the inside of the explosion-proof valve, so that the pressure inside the explosion-proof valve is consistent with the air pressure at other positions of the battery cell housing 2, thereby enabling the explosion-proof valve to open normally and release air pressure when the internal pressure is too high.
[0028] Optionally, part of the gas guide groove 11 can be set in the first part 12 opposite to the explosion-proof valve, and the other part of the groove can extend to the second part 13 or extend to the third part 14 through the second part 13, so that the gas guide groove 11 has better gas guiding performance. In this way, even in extreme cases, when the first part 12 is completely in close contact with the shell wall, the gas guide groove 11 can still guide the gas to the inside of the explosion-proof valve through the groove of the second part 13 or the third part 14, so that the explosion-proof valve can open normally when the internal pressure is too high.
[0029] It is understandable that the number and position of the second part 13 and the third part 14 of the insulating film body 1 can be adjusted according to the specific structure of the cell housing 2. Specifically, in order to facilitate the assembly of the cell, the cell housing 2 usually includes an open housing with an opening on at least one side and a cover plate. When assembling the cell, the internal components of the cell (electrode group 3, insulating film body 1, etc.) need to be installed in the open housing first, and then the cover plate is installed at the opening position of the open housing for sealing. Specifically, the side of the cover plate facing the open housing is usually provided with a plastic layer for insulation. Therefore, in order to save space inside the cell, the side of the electrode group 3 facing the cover plate does not need to be covered by the insulating film body 1.
[0030] In some embodiments, such as Figure 1 and Figure 3 As shown, there are at least two second parts 13. The two second parts 13 are arranged opposite each other, and the third part 14 is connected to at least one second part 13.
[0031] In this embodiment, the two second parts 13 are respectively connected to both sides of the first part 12, and the third part 14 is connected to one of the second parts 13, so that the insulating film body 1 can form a whole, which is convenient for transportation and storage. It is understood that the insulating film body 1 is usually a flexible film. Before installation, the insulating film body 1 can be flattened to facilitate transportation and storage. During installation, the two second parts 13 can be folded relative to the first part 12, and the third part 14 can be folded relative to the second part 13, so that the first part 12 covers the first side of the electrode group 3, the second part 13 covers the second side, and the third part 14 covers the third side.
[0032] Understandably, in the case of only two parts 13, the insulating film body 1 is mainly applicable to open shells with openings at both ends. The insulating film body 1 can cover the side of the pole group 3 opposite to the inner wall of the open shell. The side of the pole group 3 facing the openings at both ends of the open shell is mainly insulated by the plastic on the inside of the cover plate.
[0033] In some embodiments, such as Figure 1 and Figure 3 As shown, the third part 14 and the second part 13 are connected in a one-to-one correspondence, and at least a portion of the two third parts 14 are superimposed on each other.
[0034] In this embodiment, by providing two third parts 14, which are connected one-to-one with the two second parts 13, when the insulating film body 1 covers the electrode group 3, at least a portion of the film of the two third parts 14 is stacked on top of each other to cover the third side of the electrode group 3, so as to ensure the insulation between the third side of the electrode group 3 and the cell housing 2.
[0035] In some embodiments, such as Figure 1 , Figure 2 and Figure 3 As shown, the width of the electrode group 3 is A, the length is B, the dimension of the air guide groove 11 along the width direction of the electrode group 3 is a, and the dimension of the air guide groove 11 along the length direction of the electrode group 3 is b. When the air guide groove 11 is only provided in the first part 12, a satisfies: a≥0.1A; b satisfies: b≥0.1B.
[0036] In this embodiment, the length of the electrode group 3 refers to the length of the long side of the electrode group 3 facing the air guide groove 11, and the width of the electrode group 3 refers to the length of the short side of the electrode group 3 facing the air guide groove 11. This embodiment limits the lower limit of the size of the air guide groove 11 based on the length and width of the electrode group 3 to ensure the air guiding effect of the air guide groove 11, so that the gas in the air guide groove 11 can exceed the explosion-proof valve threshold to open the explosion-proof valve for exhaust and pressure relief.
[0037] It is understandable that the air guide groove 11 can be designed in any shape according to actual needs, such as cross-shaped, strip-shaped, fishbone-shaped, tree-shaped, etc. When the air guide groove 11 is irregular in shape, the dimension of the air guide groove 11 along the width direction of the pole group 3 refers to the distance between the two farthest endpoints of the air guide groove 11 along the width direction of the pole group 3; correspondingly, the dimension of the air guide groove 11 along the length direction of the pole group 3 refers to the distance between the two farthest endpoints of the air guide groove 11 along the length direction of the pole group 3.
[0038] When the air guide groove 11 extends to the second part 13 or the third part 14, the dimensions of the air guide groove 11 need to be reasonably designed in the flattened state. When designing the air guide groove 11, the height C of the electrode assembly 3 also needs to be considered. It can be understood that the height of the electrode assembly 3 is the dimension of the electrode assembly 3 perpendicular to the side facing the air guide groove 11. For example, in the flattened state, the overall width of the air guide groove 11 needs to be less than or equal to 3A+2C; the overall length of the air guide groove 11 needs to be less than or equal to B+2C.
[0039] In some embodiments, such as Figure 1 As shown, the air guide groove 11 includes a first groove 111 and a plurality of second grooves 112. The first groove 111 extends along the length direction of the pole group 3, the second grooves 112 extend along the width direction of the pole group 3, the middle part of the second groove 112 is connected to the first groove 111, and the plurality of second grooves 112 are arranged at intervals along the extension direction of the first groove 111.
[0040] In this embodiment, the first groove 111 and the second groove 112 are arranged in a cross shape so that the gas in the gap between the battery cell housing 2 and the insulating film body 1 can be introduced into the gas guide groove 11 in two directions so as to pressurize the explosion-proof valve.
[0041] In some embodiments, the width of both the first groove 111 and the second groove 112 is not less than 0.01 mm. In this embodiment, by limiting the width of the first groove 111 and the second groove 112, the first groove 111 and the second groove 112 are made wide enough to accommodate a sufficient amount of gas, so that the gas in the gas guide groove 11 can exceed the explosion-proof valve threshold to open the explosion-proof valve for exhaust and pressure relief.
[0042] In some embodiments, such as Figure 3 As shown, the thickness of the insulating film body 1 is H, and the depth of the gas guide groove 11 is h, where h satisfies: 0.001H ≤ h ≤ 0.99H. In this embodiment, the depth of the gas guide groove 11 is determined based on the thickness of the insulating film body 1, ensuring that the insulating film body 1 at the bottom of the gas guide groove 11 still has a certain thickness to guarantee the insulation effect at the location of the gas guide groove 11. At the same time, it also ensures that the gas guide groove 11 has sufficient depth to accommodate a sufficient amount of gas, so that the gas in the gas guide groove 11 can exceed the explosion-proof valve threshold to open the explosion-proof valve for exhaust and pressure relief.
[0043] Optionally, the insulating film body 1 may be made of one of the following organic or inorganic insulating films: PP (Polypropylene) film, PPS (Polyphenylenesulfide) film, PE (Polyethylene) film, PI (Polyimide) film, PET (Polyethylene terephthalate) film, mica paper, etc.
[0044] Preferably, the insulating film body 1 is one of PP film, PI film, PE film or PET film.
[0045] Optionally, the air guide groove 11 can be obtained by means of hot melting, stamping, etching or corrosion on the insulating film body 1.
[0046] On the other hand, the present invention also provides a battery cell, comprising: a battery cell housing 2, an electrode group 3, and an internal insulating film as provided in any of the above embodiments. The battery cell housing 2 is provided with a vent hole, which is equipped with an explosion-proof valve; the insulating film body 1 and the electrode group 3 are disposed within the inner cavity of the battery cell housing 2, with the insulating film body 1 covering the electrode group 3.
[0047] The battery cell of the present invention, by employing the internal insulating film of the battery cell in the above embodiments, also has the advantages of the internal insulating film of the battery cell, which will not be repeated here.
[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. An internal insulating film for a battery cell, characterized in that, include: An insulating film body is configured to be disposed between a battery cell housing and an electrode assembly to isolate the battery cell housing and the electrode assembly; the insulating film body has an air guide groove on the side facing the explosion-proof valve, at least a portion of the air guide groove is disposed opposite to the explosion-proof valve, and the air guide groove communicates with the gap between the battery cell housing and the insulating film body.
2. The internal insulating film of the battery cell according to claim 1, characterized in that, The insulating film body includes a first part, a second part, and a third part connected together. The first part covers a first side of the electrode group, the second part covers a second side of the electrode group, and the third part covers a third side of the electrode group. The first side of the electrode group is the side of the electrode group facing the explosion-proof valve, the second side is the side adjacent to the first side, and the third side is the side opposite to the first side. The air guide groove is disposed in the first part; or, the air guide groove extends from the first part to the second part; or, the air guide groove extends from the first part to the second part and the third part in sequence.
3. The internal insulating film of the battery cell according to claim 2, characterized in that, There are at least two second parts; the two second parts are arranged opposite each other, and the third part is connected to at least one of the second parts.
4. The internal insulating film of the battery cell according to claim 3, characterized in that, The third part and the second part are connected in a one-to-one correspondence, and at least a portion of the two third parts are superimposed on each other.
5. The internal insulating film of the battery cell according to claim 2, wherein the width of the electrode assembly is A and the length is B, characterized in that, The dimension of the air guide groove along the width direction of the electrode group is a, and the dimension of the air guide groove along the length direction of the electrode group is b; When the air guide groove is only provided in the first part, a satisfies: a≥0.1A; b satisfies: b≥0.1B.
6. The internal insulating film of the battery cell according to claim 1, characterized in that, The air guide channel includes a first channel and a plurality of second channels; The first groove extends along the length direction of the electrode group, the second groove extends along the width direction of the electrode group, the middle part of the second groove is connected to the first groove, and a plurality of second grooves are arranged at intervals along the extension direction of the first groove.
7. The internal insulating film of the battery cell according to claim 6, characterized in that, The width of both the first and second grooves is not less than 0.01 mm.
8. The internal insulating film of the battery cell according to claim 1, characterized in that, The thickness of the insulating film body is H, and the depth of the air guide groove is h, where h satisfies: 0.001H≤h≤0.99H.
9. The internal insulating film of the battery cell according to claim 1, characterized in that, The insulating film body is one of PP film, PI film, PE film or PET film.
10. A battery cell, characterized in that, include: The cell housing, the electrode assembly, and the internal insulating film of the cell as described in any one of claims 1-9; The battery cell housing is provided with an exhaust port, and the exhaust port is equipped with an explosion-proof valve; the insulating film body and the electrode assembly are disposed in the inner cavity of the battery cell housing, and the insulating film body covers the electrode assembly.