Winding core, battery, and vehicle

Abstract

This invention belongs to the field of battery technology and discloses a winding core, a battery, and a vehicle. The winding core has a flow groove at its end, configured to connect to a mounting hole of an explosion-proof valve. The battery includes a housing, an explosion-proof valve, and a winding core. The housing has a receiving groove, and the bottom of the receiving groove has a mounting hole connecting to the outside. The explosion-proof valve is installed in the mounting hole. The winding core is disposed in the receiving groove, and the flow groove connects to the mounting hole. The vehicle includes the aforementioned battery. In this invention, by providing a flow groove at the bottom of the winding core, the winding core is separated from the explosion-proof valve at the bottom of the housing only at the explosion-proof valve. When thermal runaway occurs, the internal gas can flow smoothly and promptly through the flow groove to the explosion-proof valve at the mounting hole, and finally be discharged from the battery through the explosion-proof valve. This ensures normal venting of the battery during thermal runaway.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a winding core, a battery, and a vehicle. Background Technology

[0002] In automotive power battery technology, in order to improve the vehicle's range, the energy density of the battery is often increased. However, high energy density inevitably brings high risks to the battery.

[0003] Thermoelectric separation technology is typically used to address the thermal runaway risk of high-energy-density batteries. This technology involves placing an explosion-proof valve and a cover plate on opposite sides of the battery. In the event of thermal runaway, the explosion-proof valve opens, and the high-temperature material inside the cell is ejected from the battery through the valve. The cover plate is located on the side opposite to the direction of the ejection. The cover plate has positive and negative terminals, both of which are conductive. Since the direction of the ejection is not on the same side of the battery as the terminals, the ejected gas flows out of the battery through the explosion-proof valve at the bottom, preventing short circuits or other safety risks to the conductive terminals.

[0004] However, the thermoelectric separation scheme results in the explosion-proof valve being tightly fitted to the battery's internal core, causing the core to contact the explosion-proof valve and damage it. Furthermore, because the explosion-proof valve is tightly fitted to the core, when thermal runaway occurs, the internal gas flow is obstructed, preventing timely discharge from the battery. Gas accumulates inside the battery, increasing the internal pressure of the battery casing, causing the casing to rupture and resulting in heat propagation.

[0005] To address the aforementioned issues, related technologies employ a plastic support within the casing to separate the core from the explosion-proof valve at the bottom of the casing. However, this approach sacrifices the battery's internal space, reducing its energy density. Summary of the Invention

[0006] The purpose of this invention is to provide a core, battery, and vehicle that can improve safety while ensuring the energy density of the battery.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] The core has a flow groove at its end, which is configured to connect to the mounting hole of the explosion-proof valve.

[0009] Preferably, the core includes a positive electrode sheet, a negative electrode sheet, and a separator, with the separator sandwiched between the positive and negative electrode sheets. The positive electrode sheet has a first inner groove at its end, and the negative electrode sheet has a second inner groove at its end. The flow groove includes the first inner groove and the second inner groove.

[0010] Preferably, along the direction away from the explosion-proof valve, the inner wall of the first inner groove is concave relative to the inner wall of the second inner groove.

[0011] Preferably, one end of the diaphragm is provided with a third inner groove, which is at least partially located in the flow groove.

[0012] Preferably, in the direction away from the explosion-proof valve, the inner wall of the second inner groove is concave relative to the inner wall of the third inner groove.

[0013] The battery includes a casing, an explosion-proof valve, and the aforementioned winding core;

[0014] The housing is provided with a receiving groove, and the bottom of the receiving groove is provided with a mounting hole communicating with the outside of the housing;

[0015] The explosion-proof valve is installed in the mounting hole;

[0016] The core is disposed in the receiving groove, and the flow groove is connected to the mounting hole.

[0017] Preferably, the orthographic projection of the flow channel onto the bottom of the receiving groove covers the mounting hole.

[0018] Preferably, the housing is provided with at least two mounting holes, each mounting hole is equipped with the explosion-proof valve, and each mounting hole is connected to the flow groove.

[0019] Preferably, the device also includes an insulating tray, which is disposed in the receiving groove and sandwiched between the bottom of the receiving groove and the winding core.

[0020] Preferably, the insulating tray includes a main body area and a detachable area connected to the main body area. The orthographic projection of the detachable area onto the bottom of the receiving groove covers the mounting hole, and the thickness of the detachable area where it connects to the main body area is less than the thickness of the main body area.

[0021] Preferably, the insulating tray is provided with an annular groove, which surrounds the insulating tray to form a detachment area.

[0022] A vehicle, including a vehicle body and the aforementioned battery, wherein the battery is mounted on the vehicle body.

[0023] The beneficial effects of this invention are:

[0024] By setting a flow channel at the bottom of the core, the core is separated from the explosion-proof valve at the bottom of the casing only at the explosion-proof valve. When thermal runaway occurs, the internal gas can flow smoothly through the flow channel to the explosion-proof valve at the mounting hole in a timely manner, and finally be discharged from the battery through the explosion-proof valve. This can ensure normal venting of the battery when thermal runaway occurs, thereby reducing the occurrence of thermal runaway. At the same time, it can accelerate the venting speed of internal gas, improve the venting effect of the battery, improve the safety of the battery, and prevent gas from accumulating inside the battery, which would increase the internal pressure of the casing, causing the casing to rupture and causing heat propagation. This solves the problem of unstable opening of the bottom explosion-proof valve in the thermoelectric separation scheme, which is prone to shortening the life due to core compression. Moreover, it does not increase the extra space and has no new parts. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a battery according to an embodiment of the present invention;

[0026] Figure 2 This is a cross-sectional view of a battery according to an embodiment of the present invention;

[0027] Figure 3 yes Figure 2 A magnified view of a portion of the image;

[0028] Figure 4 This is a schematic diagram of the stacking of the positive electrode sheet and the separator of a wound core according to an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the stacking of the negative electrode sheet and the separator of a wound core according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the stacking of the positive electrode sheet and the separator of another type of winding core according to an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the stacking of the negative electrode sheet and the separator of another type of winding core according to an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of the insulating tray described in an embodiment of the present invention;

[0033] Figure 9 This is a partial cross-sectional view of the insulating tray described in an embodiment of the present invention;

[0034] Figure 10 This is a partial cross-sectional view of another battery according to an embodiment of the present invention;

[0035] Figure 11 This is a bottom view of another battery described in an embodiment of the present invention.

[0036] In the picture:

[0037] 1. Housing; 11. Receiving groove; 100. Mounting hole;

[0038] 2. Core; 200. Flow groove; 21. Positive electrode plate; 211. First inner groove; 22. Negative electrode plate; 221. Second inner groove; 23. Separator; 231. Third inner groove;

[0039] 3. Insulating support plate; 31. Annular groove;

[0040] 4. Cover plate assembly. Detailed Implementation

[0041] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0042] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0045] like Figures 1-11 As shown, the present invention provides a core 2, the end of which is provided with a flow groove 200, the flow groove 200 being configured to communicate with the mounting hole 100 of the explosion-proof valve on the housing 1.

[0046] In this invention, by setting a flow groove 200 at the bottom of the core 2, the core 2 is separated from the explosion-proof valve at the bottom of the housing 1 only at the explosion-proof valve. When thermal runaway occurs, the internal gas can flow smoothly through the flow groove 200 to the explosion-proof valve at the mounting hole 100 in a timely manner, and finally be discharged from the battery through the explosion-proof valve. This can ensure normal venting of the battery when thermal runaway occurs, thereby reducing the occurrence of thermal runaway. At the same time, it can accelerate the venting speed of the internal gas, improve the venting effect of the battery, improve the safety of the battery, and prevent gas from accumulating inside the battery, causing the internal pressure of the housing 1 to rise, resulting in the rupture of the housing 1 and causing heat propagation. This solves the problem of unstable opening of the bottom explosion-proof valve in the thermoelectric separation scheme, which is prone to shortening the life due to the pressure of the core 2. Moreover, it does not increase the extra space and has no new parts.

[0047] In this embodiment, the flow channel 200 is disposed at the end of the winding core 2 facing the explosion-proof valve. In other embodiments, the flow channel 200 may also be disposed at the end of the winding core 2 away from the explosion-proof valve.

[0048] Specifically, the core 2 includes a positive electrode 21, a negative electrode 22, and a separator 23. The separator 23 is sandwiched between the positive electrode 21 and the negative electrode 22. After the positive electrode 21, the negative electrode 22, and the separator 23 are stacked, they extend in a serpentine bend. The end of the positive electrode 21 is provided with a first inner groove 211, and the end of the negative electrode 22 is provided with a second inner groove 221. The flow groove 200 includes the first inner groove 211 and the second inner groove 221. The above arrangement enables the flow groove 200 to be formed efficiently and reliably on the core 2.

[0049] More specifically, along the direction away from the explosion-proof valve, the inner wall of the first inner groove 211 is concave relative to the inner wall of the second inner groove 221. That is, the distance between the bottom of the first inner groove 211 and the explosion-proof valve is greater than the distance between the bottom of the second inner groove 221 and the explosion-proof valve. Furthermore, along the length of the core 2, the size of the first inner groove 211 is larger than the size of the second inner groove 221. This arrangement ensures the safety of the core 2 at the flow channel 200.

[0050] Specifically, a third inner groove 231 is provided at one end of the diaphragm 23, and the third inner groove 231 is at least partially located in the flow channel 200. The above arrangement, while ensuring the safety of the core 2 at the flow channel 200, reduces the resistance of the diaphragm 23 to gas flow in the event of thermal runaway.

[0051] More specifically, the third inner groove 231 is entirely located within the flow groove 200, and the inner wall of the second inner groove 221 is concave relative to the inner wall of the third inner groove 231. This arrangement further ensures the safety of the core 2 at the flow groove 200.

[0052] In this embodiment, as Figure 4 and Figure 5 As shown, at the flow channel 200, a third inner groove 231 is provided at one end of the diaphragm 23 facing the bottom of the receiving channel 11. Along the direction away from the explosion-proof valve, the inner wall of the second inner groove 221 is concave relative to the inner wall of the third inner groove 231. That is, the distance between the bottom of the second inner groove 221 and the explosion-proof valve is greater than the distance between the bottom of the third inner groove 231 and the explosion-proof valve. In addition, in the length direction of the core 2, the size of the second inner groove 221 is greater than the size of the third inner groove 231. The design principle of the electrode is that the area of ​​the separator 23 should be larger than the area of ​​the negative electrode 22, and the area of ​​the negative electrode 22 should be larger than the area of ​​the positive electrode 21. In the height direction of the battery, the size of the separator 23 is larger than the size of the negative electrode 22, and the size of the negative electrode 22 is larger than the size of the positive electrode 21. Thus, the end of the separator 23 facing the bottom of the receiving groove 11 protrudes relative to the negative electrode 22, and the end of the negative electrode 22 facing the bottom of the receiving groove 11 protrudes relative to the positive electrode 21. In this application, the positive electrode 21 and the negative electrode 22 maintain this principle at the slot position.

[0053] In another embodiment, such as Figure 6 and Figure 7 As shown, at the flow channel 200, the diaphragm 23 extends to the opening of the flow channel 200. This arrangement eliminates the need for processing the diaphragm 23, reducing manufacturing costs and improving manufacturing efficiency.

[0054] like Figures 1-11 As shown, the present invention provides a battery, including a housing 1, an explosion-proof valve, and the aforementioned winding core 2. The housing 1 has a receiving groove 11, the bottom of which has a mounting hole 100 communicating with the outside. The explosion-proof valve is installed in the mounting hole 100. The winding core 2 is disposed in the receiving groove 11, and a flow groove 200 is provided at one end of the winding core 2 facing the bottom of the receiving groove 11, the flow groove 200 communicating with the mounting hole 100.

[0055] In this invention, by setting a flow groove 200 at the bottom of the core 2, the core 2 is separated from the explosion-proof valve at the bottom of the housing 1 only at the explosion-proof valve, thereby improving the utilization rate of the space in the accommodating groove 11, ensuring the energy density of the battery, and preventing the core 2 from damaging the explosion-proof valve. When thermal runaway occurs, the internal gas can flow smoothly through the flow groove 200 to the explosion-proof valve at the mounting hole 100 in a timely manner, and finally be discharged from the battery through the explosion-proof valve. This can ensure the normal venting of the battery when thermal runaway occurs, thereby reducing the occurrence of thermal runaway. At the same time, it can accelerate the venting speed of the internal gas, improve the venting effect of the battery, improve the safety of the battery, and prevent the gas from accumulating inside the battery, causing the internal pressure of the housing 1 to rise, resulting in the rupture of the housing 1 and causing heat propagation. This solves the problem of unstable opening of the bottom explosion-proof valve in the thermoelectric separation scheme, which is prone to shortening the life due to the pressure of the core 2, without adding extra space or new parts.

[0056] In this embodiment, the explosion-proof valve is a metal sheet welded into the mounting hole 100. When subjected to force, it can break to open the mounting hole 100. Its specific structure and working principle are existing technologies and will not be described in detail here.

[0057] Specifically, the orthographic projection of the flow channel 200 onto the bottom of the receiving channel 11 covers the mounting hole 100. This arrangement allows the flow channel 200 to be fully connected to the mounting hole 100, making the flow of gas smoother during thermal runaway.

[0058] In one embodiment, such as Figure 1 and Figure 2 As shown, a mounting hole 100 is provided on the housing 1, and an explosion-proof valve is installed in the mounting hole 100. The mounting hole 100 is connected to a flow channel 200.

[0059] In another embodiment, the housing 1 is provided with at least two mounting holes 100, for example... Figure 10 and Figure 11 As shown, the housing 1 is provided with three mounting holes 100, each of which is equipped with an explosion-proof valve. Each mounting hole 100 is connected to a flow groove 200, which makes the gas discharge more efficient and rapid in the event of thermal runaway.

[0060] Specifically, the battery also includes an insulating tray 3, which is disposed in the receiving groove 11 and sandwiched between the bottom of the receiving groove 11 and the winding core 2. By providing the insulating tray 3, direct contact between the winding core 2 and the bottom of the receiving groove 11 of the housing 1 is avoided, thus achieving an insulating effect.

[0061] More specifically, the insulating support plate 3 includes a main body area and a detachment area connected to the main body area. The orthogonal projection of the detachment area onto the bottom of the receiving groove 11 covers the mounting hole 100, and the thickness of the detachment area where it connects to the main body area is less than the thickness of the main body area. By setting a thinned detachment area, the detachment area can open rapidly in the event of thermal runaway, thereby further improving the safety of the battery.

[0062] More specifically, the insulating tray 3 is provided with an annular groove 31, which surrounds the insulating tray 3 to form a detachment area. The above-mentioned configuration makes the processing of the detachment area simpler and more convenient.

[0063] In this embodiment, the area at the annular groove 31 is a detachment area. A detachment area is set for each mounting hole 100. That is, when there is one mounting hole 100, a corresponding detachment area is set on the insulating plate 3. When there are three mounting holes 100, three corresponding detachment areas are set on the insulating plate 3.

[0064] In other embodiments, the detachment area can be thinned as a whole to a uniform thickness, so that the overall thickness of the detachment area is less than the thickness of the main body area.

[0065] In this embodiment, the battery also includes a cover plate assembly 4, which is connected to the housing 1 and covers the opening of the receiving groove 11. The cover plate assembly 4 is provided with a positive electrode post and a negative electrode post. The positive electrode plate 21 is connected to the positive electrode post through an electrode tab, and the negative electrode plate 22 is connected to the negative electrode post through an electrode tab.

[0066] The cover plate assembly 4 of the battery covers the receiving groove 11 of the housing 1 to form a receiving cavity. The core 2 is set inside the receiving cavity. The core 2 is stacked by positive electrode 21, negative electrode 22 and separator 23. The bottom surface of the receiving groove 11 is set as the first plane. The explosion-proof valve is welded in the mounting hole 100 and its height is lower than the first plane. There is a gap between the positive electrode 21, negative electrode 22 and separator 23 and the explosion-proof valve. That is, in the area opposite to the explosion-proof valve, the positive electrode 21, negative electrode 22 and separator 23 are laser cut to leave a groove, namely the flow groove 200, so that there is a gap between the first plane and the core 2.

[0067] There is a mounting hole 100 on the first plane, and a flow groove 200 is provided at the position of the core 2 opposite to the mounting hole 100. The flow groove 200 is opposite to the mounting hole 100 and is formed by stacking multiple layers of electrode sheets and diaphragms 23 after laser cutting at the same position. The dimension of the explosion-proof valve in the length direction of the housing 1 is A. The flow groove 200 takes the bottom of the second inner groove 221, the groove wall of the second inner groove 221, and the groove opening of the third inner groove 231 as the reference for its own dimension. The dimension of the flow groove 200 in the length direction is B. Then B≥A. The orthographic projection area of ​​the flow groove 200 on the first plane is ≥ the mounting hole 1 on the first plane of the housing 1. The orthographic projection area of ​​the explosion-proof valve is 00, and the orthographic projection of the mounting hole 100 is entirely within the orthographic projection of the flow groove 200 on the first plane. Since the size of the core 2 is smaller than the size of the receiving groove 11 in the housing 1, the center position of the core 2 cannot be guaranteed after assembly. Therefore, the flow groove 200 is generally larger than the mounting hole 100 in the initial design. In the orthographic projection of the first plane, the single-sided gap between the flow groove 200 and the mounting hole 100 is ≥0.5mm. The depth of the flow groove 200 is 0.5mm-3mm to avoid insufficient depth from failing to effectively exhaust air, and excessive depth from affecting the size of the cell electrode, resulting in a reduction in the effective reaction area of ​​the electrode.

[0068] An insulating support plate 3 is provided between the core 2 and the first plane inside the shell 1. The insulating support plate 3 isolates the core 2 from the first plane of the shell 1 and serves as insulation. In traditional thermoelectric separation schemes, the insulating support plate 3 has no weak area at the explosion-proof valve position, which hinders the internal gas from escaping the battery during thermal runaway, resulting in an increase in the internal gas pressure of the battery. There is a risk that the shell 1 will rupture due to the increased internal gas pressure caused by the untimely gas escaping. In this application, a thinning process is performed at the position corresponding to the mounting hole 100 on the first plane of the insulating support plate 3 to form a detachment area. An annular groove 31, i.e., a thinning mark, is opened on the insulating support plate 3 to form a detachment area. The orthogonal projection of the thinning mark in the first plane is 0-5mm away from the edge of the mounting hole 100. The depth of the thinning mark accounts for 10%-90% of the thickness of the insulating support plate 3. The surface of the thinning mark faces the first plane at the bottom of the shell 1, which can ensure that the mark of the insulating support plate 3 opens quickly.

[0069] This embodiment also provides a vehicle, including a vehicle body and the aforementioned battery, with the battery installed in the vehicle body.

[0070] In the vehicle of this invention, by providing a flow groove 200 at the bottom of the core 2, the core 2 is separated from the explosion-proof valve at the bottom of the housing 1 only at the explosion-proof valve, thereby improving the utilization rate of the space within the accommodating groove 11, ensuring the energy density of the battery, and preventing the core 2 from damaging the explosion-proof valve. When thermal runaway occurs, the internal gas can flow smoothly through the flow groove 200 to the explosion-proof valve at the mounting hole 100 in a timely manner, and finally be discharged from the battery through the explosion-proof valve. This can ensure normal venting of the battery when thermal runaway occurs, thereby reducing the occurrence of thermal runaway. At the same time, it can accelerate the venting speed of the internal gas, improve the venting effect of the battery, improve the safety of the battery, and prevent gas from accumulating inside the battery, causing the internal pressure of the housing 1 to rise, leading to the rupture of the housing 1 and causing heat propagation. This solves the problem of unstable opening of the bottom explosion-proof valve in the thermoelectric separation scheme, which is prone to shortening the life due to pressure from the core 2, without adding extra space or new parts.

[0071] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A winding core, characterized in that, The end of the winding core is provided with a flow groove (200), which is configured to communicate with the mounting hole (100) of the explosion-proof valve.

2. The winding core according to claim 1, characterized in that, The winding core includes a positive electrode sheet (21), a negative electrode sheet (22), and a separator (23). The separator (23) is sandwiched between the positive electrode sheet (21) and the negative electrode sheet (22). The positive electrode sheet (21) has a first inner groove (211) at its end, and the negative electrode sheet (22) has a second inner groove (221) at its end. The flow groove (200) includes the first inner groove (211) and the second inner groove (221).

3. The winding core according to claim 2, characterized in that, Along the direction away from the explosion-proof valve, the inner wall of the first inner groove (211) is concave relative to the inner wall of the second inner groove (221).

4. The winding core according to claim 2 or 3, characterized in that, The end of the diaphragm (23) is provided with a third inner groove (231), which is at least partially located in the flow channel (200).

5. The winding core according to claim 4, characterized in that, Along the direction away from the explosion-proof valve, the inner wall of the second inner groove (221) is concave relative to the inner wall of the third inner groove (231).

6. A battery, characterized in that, Includes a housing (1), an explosion-proof valve, and a core as described in any one of claims 1-5; The housing (1) is provided with a receiving groove (11), and the bottom of the receiving groove (11) is provided with a mounting hole (100) communicating with the outside of the housing (1); The explosion-proof valve is installed in the mounting hole (100); The core is disposed in the receiving groove (11), and the flow groove (200) is connected to the mounting hole (100).

7. The battery according to claim 6, characterized in that, The orthographic projection of the flow channel (200) onto the bottom of the receiving channel (11) covers the mounting hole (100).

8. The battery according to claim 7, characterized in that, The housing (1) is provided with at least two mounting holes (100), each mounting hole (100) is equipped with the explosion-proof valve, and each mounting hole (100) is connected to the flow groove (200).

9. The battery according to any one of claims 6-8, characterized in that, It also includes an insulating tray (3), which is disposed in the receiving groove (11) and sandwiched between the bottom of the receiving groove (11) and the winding core.

10. The battery according to claim 9, characterized in that, The insulating tray (3) includes a main body area and a detachment area connected to the main body area. The orthographic projection of the detachment area onto the bottom of the receiving groove (11) covers the mounting hole (100). The thickness of the detachment area where it connects to the main body area is less than the thickness of the main body area.

11. The battery according to claim 10, characterized in that, The insulating tray (3) is provided with an annular groove (31), which forms a detachment area on the insulating tray (3).

12. A vehicle, characterized in that, It includes a vehicle body and a battery as described in any one of claims 6-11, wherein the battery is mounted on the vehicle body.

Images