Lithium battery with self-protection function

Abstract

The invention belongs to the technical field of lithium batteries, and particularly relates to a lithium battery with a self-protection function, which comprises a shell, a BMS (Battery Management System) protection plate, a battery bracket and a lithium battery assembly, the BMS protection plate and the lithium battery assembly are arranged in the shell through the battery bracket, and the lithium battery also comprises a base fixed at the bottom of the shell, a groove is formed in the bottom of the base, a protection plate is slidably connected into the groove, a plurality of elastic telescopic rods are fixedly connected to the bottom of the base in an inserted mode, and the movable ends of the elastic telescopic rods are fixedly connected with the end face of the protection plate. The lithium battery assembly can be effectively and automatically buffered and protected from the bottom, the falling damage risk is reduced, the bottom protection effect can be enhanced and the self-protection capability can be improved in cooperation with the liquid buffering assembly, meanwhile, overheating can be avoided through auxiliary heat dissipation of the heat dissipation unit, the impact influence of the side wall is reduced by means of the force unloading sleeve, and the protection effect is comprehensively improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, and in particular relates to a lithium battery with self-protection function. Background Technology

[0002] Battery swapping lithium batteries are widely used in industries such as food delivery and express delivery. By quickly replacing batteries with fully charged ones, they solve the range anxiety of electric vehicles, meet the efficient and continuous power needs of high-frequency operation scenarios, and help industries improve operational efficiency.

[0003] Currently, since lithium batteries need to be replaced frequently and people come into direct contact with them, the protective function of lithium batteries is very important. For example, a lithium battery cover structure with a built-in safety protection structure is disclosed in patent publication number CN110379952A. During frequent disassembly and relocation of lithium batteries, they often fall due to improper handling, resulting in direct impact to the bottom. Traditional lithium battery bottom protection often uses thickened outer shell materials, such as high-strength plastic or metal shells. However, this method can only withstand small impacts to a certain extent. When a lithium battery falls, a larger impact force will act directly on the bottom. The thickened shell cannot adequately buffer and disperse the energy, which can easily cause the shell to deform, damaging the internal structure of the lithium battery and increasing the probability of subsequent safety hazards such as fire and explosion. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a lithium battery with a self-protection function.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a lithium battery with self-protection function, comprising a casing, a BMS protection board, a battery bracket, and a lithium battery assembly, wherein the BMS protection board and the lithium battery assembly are mounted inside the casing via the battery bracket, and further comprising: The base is fixed to the bottom of the outer shell. The bottom of the base has a groove, and a protective plate is slidably connected inside the groove. Several elastic telescopic rods are fixedly inserted into the bottom of the base, and the movable end of the elastic telescopic rod is fixedly connected to the end face of the protective plate. A liquid buffer assembly is installed inside the groove and above the protective plate; The top cover is fixed to the top of the outer casing, and the top cover and the base are together equipped with a heat dissipation unit.

[0006] Preferably, the liquid buffer assembly includes an elastic bladder fixed to the top of the groove, and the elastic bladder is positioned above the protective plate. A pressing frame for pressing the outer edge of the elastic bladder is fixed to the bottom of the groove, and the interior of the elastic bladder is filled with buffer solution.

[0007] Preferably, the heat dissipation unit includes a lower liquid channel formed at the top of the groove, and the lower liquid channel is located inside the elastic bladder. The top of the top cover has an upper liquid channel, and the top of the top cover is fixedly encapsulated with a sealing cover plate that matches the upper liquid channel. The battery bracket is fixedly connected with multiple connecting pipes. The lower liquid channel is connected to the upper liquid channel through the connecting pipes. Multiple support pipes are fixedly connected between the top cover and the base at the outer side of the outer shell. Frame-shaped cavities are formed at the inner outer edges of both the top cover and the base, and each support pipe is connected to two frame-shaped cavities. Multiple horizontal pipes connected to the frame-shaped cavities on the same side are fixedly connected to the walls of the upper and lower liquid channels. The protective plate and the pressing frame are jointly installed with a pressure driving assembly for compressing the elastic bladder. The upper liquid channel, lower liquid channel, connecting pipes, support pipes, and frame-shaped cavities are also filled with buffer solution.

[0008] Preferably, the pressurization drive assembly includes a mounting groove formed on the top of the protective plate, and a pressure plate is slidably connected inside the mounting groove. The pressure plate is located below the elastic bladder. Multiple iron blocks are fixedly inserted into the top outer edge of the pressure plate. Multiple electromagnetic blocks corresponding to the positions of the iron blocks are fixedly installed at the bottom of the pressing frame, and the electromagnetic blocks are electrically connected to the control terminal of the BMS protection board.

[0009] Preferably, the outer wall of the support tube is rotatably fitted with a stress-relieving sleeve, and the side walls of two adjacent stress-relieving sleeves are in contact.

[0010] Preferably, a set of temperature probes is fixed at the bottom of the sealing cover inside the upper liquid channel, and the BMS protection board controls the electromagnetic block to work according to the electrical signal fed back by the temperature probes.

[0011] Preferably, a one-way valve is installed inside the support tube, and the buffer solution flows from the upper opening to the lower opening along the one-way valve. The inlet end of each horizontal tube located at the upper liquid channel is lower than the upper opening of the connecting tube.

[0012] Preferably, the external interface of the BMS protection board is located on the side wall of the housing, and the support tube and the stress relief sleeve are offset from the external interface of the BMS protection board. The top cover and the base are rotatably connected to a rotating roller at opposite ends, and the rotating roller is located on the upper and lower sides of the external interface of the BMS protection board. The rotating roller contacts the side wall of the stress relief sleeve on the same side, and the side walls of two adjacent rotating rollers on the same side are in contact.

[0013] Compared with existing technologies, the advantages of a lithium battery with self-protection function are: 1. Through the coordinated design of the outer shell, base, protective plate, and several elastic telescopic rods, the lithium battery assembly can be buffered and protected from the bottom, minimizing damage to the lithium battery caused by it falling during battery swapping. Secondly, the liquid buffer component further enhances the automatic buffering and protection effect on the bottom of the lithium battery using the buffer solution, resulting in good self-protection.

[0014] 2. The heat dissipation unit, in conjunction with the liquid buffer component, can assist in heat dissipation of the lithium battery assembly, thereby minimizing the risk of overheating during charging and discharging.

[0015] 3. The shock-absorbing sleeve, in conjunction with the support tube for heat dissipation, provides impact protection from the side wall of the outer casing. By utilizing the rotational action, it can effectively reduce the impact of side wall impact on the lithium battery assembly, further improving the protection effect of the lithium battery assembly. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a lithium battery with self-protection function provided by the present invention; Figure 2 This is a cross-sectional structural diagram of a lithium battery with self-protection function provided by the present invention; Figure 3 This is a top view of the internal structure of the casing of a lithium battery with self-protection function provided by the present invention; Figure 4 This invention provides a lithium battery with a self-protection function. Figure 2 Enlarged view of the structure of part A in the middle.

[0017] In the diagram: 1. Outer shell, 2. BMS protection board, 3. Battery bracket, 4. Lithium battery assembly, 5. Base, 6. Groove, 7. Protective plate, 8. Elastic telescopic rod, 9. Liquid buffer assembly, 91. Elastic bladder, 92. Press-fit frame, 10. Top cover, 11. Heat dissipation unit, 111. Lower liquid channel, 112. Upper liquid channel, 113. Sealing cover, 114. Connecting pipe, 115. Support pipe, 116. Frame cavity, 117. Horizontal pipe, 12. Pressurization drive assembly, 121. Mounting groove, 122. Pressurization plate, 123. Iron block, 124. Electromagnetic block, 13. Unloading sleeve, 14. Temperature probe, 15. One-way valve, 16. Rotating roller. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] like Figures 1-4As shown, a lithium battery with self-protection function includes a housing 1, a BMS protection board 2, a battery bracket 3, and a lithium battery assembly 4. The BMS protection board 2 and the lithium battery assembly 4 are installed inside the housing 1 through the battery bracket 3. The battery assembly 4 also includes a base 5, which is fixed to the bottom of the housing 1. A groove 6 is provided on the bottom of the base 5, and a protective plate 7 is slidably connected inside the groove 6. Several elastic telescopic rods 8 are fixedly inserted into the bottom of the base 5, and the movable end of the elastic telescopic rod 8 is fixedly connected to the end face of the protective plate 7.

[0020] The liquid buffer assembly 9 is installed inside the groove 6 and above the protective plate 7. The liquid buffer assembly 9 includes an elastic bladder 91 fixed to the top of the groove 6 and the elastic bladder 91 is positioned above the protective plate 7. A crimping frame 92 is fixed to the bottom of the groove 6 to crimp the outer edge of the elastic bladder 91. The interior of the elastic bladder 91 is filled with a buffer solution. The buffer solution is a liquid with high viscosity resistance and no corrosion, such as a phosphate ester liquid. Nano thermally conductive particles, such as alumina and graphene, are added to the buffer solution.

[0021] The top cover 10 is fixed to the top of the outer shell 1, and the top cover 10 and the base 5 are jointly equipped with a heat dissipation unit 11. The heat dissipation unit 11 includes a lower liquid channel 111 opened on the top of the groove 6, and the lower liquid channel 111 is located inside the elastic bladder 91. The top of the top cover 10 has an upper liquid channel 112, and the top of the top cover 10 is fixedly sealed with a sealing cover plate 113 that matches the upper liquid channel 112. The battery bracket 3 is fixedly connected with multiple connecting pipes 114. The lower liquid channel 111 is connected to the upper liquid channel 112 through the connecting pipes 114. Multiple support pipes 1 are fixedly inserted between the top cover 10 and the base 5 at a position on the outside of the outer shell 1. 15. A frame-shaped cavity 116 is provided at the inner outer edge of the top cover 10 and the base 5, and each support tube 115 is connected to the two frame-shaped cavities 116. Multiple horizontal tubes 117 connected to the frame-shaped cavity 116 on the same side are fixedly inserted into the walls of the upper liquid channel 112 and the lower liquid channel 111. The protective plate 7 and the crimping frame 92 are jointly equipped with the pressurizing drive assembly 12 for compressing the elastic bladder 91. The upper liquid channel 112, the lower liquid channel 111, the connecting tube 114, the support tube 115, and the frame-shaped cavity 116 are also filled with buffer solution. The liquid level of the buffer solution inside the upper liquid channel 112 is two-thirds of the depth of the upper liquid channel 112.

[0022] The pressurization drive assembly 12 includes a mounting groove 121 formed on the top of the protective plate 7, and a pressure plate 122 is slidably connected inside the mounting groove 121. The pressure plate 122 is located below the elastic bladder 91. Multiple iron blocks 123 are fixedly inserted into the top outer edge of the pressure plate 122. Multiple electromagnetic blocks 124 corresponding to the positions of the iron blocks 123 are fixedly installed at the bottom of the pressing frame 92. The electromagnetic blocks 124 are electrically connected to the control terminal of the BMS protection board 2. The pressure plate 122 and the pressing frame 92 are both non-magnetic structures and are equipped with electromagnetic shielding structures. A reset spring is also provided between the bottom of the pressure plate 122 and the mounting groove 121 to drive the pressure plate 122 to move back and reset.

[0023] The outer wall of the support tube 115 is rotatably fitted with a stress relief sleeve 13, and the side walls of two adjacent stress relief sleeves 13 are in contact. Under the rotation of the stress relief sleeve 13 and the friction of the adjacent stress relief sleeves 13, the lateral impact force can be effectively dissipated.

[0024] A set of temperature probes 14 are fixed at the bottom of the sealing cover plate 113 inside the upper liquid tank 112. The BMS protection board 2 controls the electromagnetic block 124 to work according to the electrical signal fed back by the temperature probes 14. The temperature probes 14 can convert the temperature into an electrical signal and feed it back to the BMS protection board 2.

[0025] A one-way valve 15 is installed inside the support tube 115, and the buffer solution flows from the upper opening of the one-way valve 15 to the lower opening. The inlet end of each horizontal tube 117 located at the upper liquid channel 112 is lower than the upper opening of the connecting tube 114. Under the action of the one-way valve 15, the buffer solution can flow downward quickly and fill the interior of the elastic bladder 91, ensuring the buffer solution's buffering effect on the bottom impact force. Secondly, it can ensure that the buffer solution can circulate from the center of the lithium battery to the outer edge.

[0026] The external interface of the BMS protection board 2 is located on the side wall of the housing 1, and the support tube 115 and the stress relief sleeve 13 are staggered from the external interface of the BMS protection board 2. The top cover 10 and the base 5 are rotatably connected to the opposite ends of the rotating rollers 16, and the rotating rollers 16 are located on the upper and lower sides of the external interface of the BMS protection board 2. The rotating rollers 16 are in contact with the side wall of the stress relief sleeve 13 on the same side, and the side walls of two adjacent rotating rollers 16 on the same side are in contact. In order to avoid affecting the connection with the lithium battery, the coverage and protection area of ​​the housing 1 can be increased as much as possible, and the possibility of the side of the housing 1 being directly damaged by impact can be reduced.

[0027] The operating principle of this invention is explained as follows: When a battery replacement is needed, the lithium battery is removed and the entire lithium battery is taken out through the grip on the top of the casing 1. Since the entire lithium battery is suspended in the air at this time, the protective plate 7 moves down under the action of gravity, and the buffer solution fills the elastic bladder 91 under the action of gravity. If the lithium battery falls during the removal process, the protective plate 7 will hit the ground first. At this time, under the elastic support of the elastic telescopic rod 8, the elastic telescopic rod 8 will first buffer the impact force. At the same time, the protective plate 7 and the groove 6 will undergo relative displacement, and the protective plate 7 will compress. The elastic bladder 91 compresses the buffer solution inside the elastic bladder 91. Since the support tube 115 is equipped with a one-way valve 15, the buffer solution can only flow from the upper opening to the lower opening along the one-way valve 15. Therefore, when the buffer solution is compressed, it can only flow upward through the liquid tank 112 via each connecting tube 114. By utilizing the viscous resistance of the buffer solution flowing in the narrow connecting tube 114, the impact force can be further dissipated. Thus, through the double buffering effect, the impact force on the bottom of the lithium battery assembly 4 when the lithium battery is dropped can be effectively reduced. Secondly, during normal use, the lithium battery is either installed inside an electric vehicle (which supplies power to the vehicle) or inside the charging box of a battery swapping device (which charges the battery). Therefore, the protective plate 7 at the bottom of the lithium battery is supported. At this time, the protective plate 7 will abut against the bottom of the base 5, and the protective plate 7 will compress the elastic cover 91, causing the buffer solution to fill the upper liquid channel 112, lower liquid channel 111, connecting pipe 114, support pipe 115, and frame cavity 116. During the charging and discharging process of the lithium battery, if the operating temperature of the lithium battery assembly 4 rises, the heat will be conducted upwards to the upper liquid channel 112. When the temperature probe 14 detects a temperature exceeding the threshold (which can be set via the BMS protection board 2, typically 45°C), the electrical signal strength fed back to the BMS protection board 2 by the temperature probe 14 simultaneously exceeds the threshold (the electrical signal strength corresponding to 45°C is 10mA). At this time, the BMS protection board 2 will immediately control the electromagnetic block 124 to operate at a frequency of energizing for 5 seconds and de-energizing for 5 seconds. The energized electromagnetic block 124 generates a magnetic attraction force on the iron block 123, thereby attracting the iron block 123 to move the pressure plate 122 upward. The pressure plate 122 will further compress the elastic capsule 91, thereby driving the buffer solution to flow upward into the liquid tank 112 along the connecting tube 114. When the electromagnetic block 124 is de-energized, under the elastic action of the elastic bladder 91 and the gravity of the pressure plate 122, the pressure plate 122 moves back to its original position. At this time, some buffer solution moves back into the elastic bladder 91 through the connecting tube 114. Since the inlet end of the horizontal tube 117 at the upper liquid channel 112 is lower than the upper opening of the connecting tube 114, most of the buffer solution in the upper liquid channel 112 will enter the upper frame cavity 116 through the horizontal tube 117, and then flow back into the elastic bladder 91 through the various support tubes 115, the one-way valve 15, and the lower horizontal tube 117. Therefore, under the intermittent energization of the electromagnetic block 124, the buffer solution can be driven along the lower liquid channel 11... 1. The connecting pipe 114, the upper liquid tank 112, the upper horizontal pipe 117, the upper frame cavity 116, the support pipe 115, the lower frame cavity 116 and the lower horizontal pipe 117 circulate. Since the connecting pipe 114 is located inside the battery bracket 3 and close to each lithium battery cell of the lithium battery assembly 4, when the buffer solution passes through the inside of the connecting pipe 114, it can exchange heat with the area around the lithium battery cells of the lithium battery assembly 4 and carry the heat to each support pipe 115. This can transfer the heat at the center of the lithium battery to the outer edge of the lithium battery, thereby increasing the heat dissipation area, improving the heat dissipation efficiency, and avoiding excessive heat accumulation, thus assisting in the heat dissipation of the lithium battery. Meanwhile, since the outer side of each support tube 115 is rotatably fitted with a stress relief sleeve 13, if an impact occurs from the side of the vertical part of the outer casing 1 during the replacement of the lithium battery, the impacting object will first hit each stress relief sleeve 13. Since the stress relief sleeve 13 is rotatable and each stress relief sleeve 13 is in contact with each other, the lateral impact force can be consumed under the deflection action of the stress relief sleeve 13 and the mutual friction action of adjacent stress relief sleeves 13, so as to minimize the impact of the lateral impact force on the lithium battery assembly 4.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lithium battery with self-protection function, comprising a casing (1), a BMS protection board (2), a battery bracket (3), and a lithium battery assembly (4), wherein the BMS protection board (2) and the lithium battery assembly (4) are mounted inside the casing (1) via the battery bracket (3), characterized in that, Also includes: The base (5) is fixed to the bottom of the outer shell (1). The bottom of the base (5) is provided with a groove (6), and a protective plate (7) is slidably connected inside the groove (6). Several elastic telescopic rods (8) are fixedly inserted into the bottom of the base (5), and the movable end of the elastic telescopic rod (8) is fixedly connected to the end face of the protective plate (7). A liquid buffer assembly (9) is installed inside the groove (6) and above the protective plate (7); The top cover (10) is fixed to the top of the outer shell (1), and the top cover (10) and the base (5) are together equipped with a heat dissipation unit (11).

2. A lithium battery with self-protection function according to claim 1, characterized in that, The liquid buffer assembly (9) includes an elastic bladder (91) fixed to the top of the groove (6), and the elastic bladder (91) is positioned above the protective plate (7). The bottom of the groove (6) is fixed with a crimping frame (92) for crimping the outer edge of the elastic bladder (91). The interior of the elastic bladder (91) is filled with buffer solution.

3. A lithium battery with self-protection function according to claim 2, characterized in that, The heat dissipation unit (11) includes a lower liquid channel (111) opened at the top of the groove (6), and the lower liquid channel (111) is located inside the elastic bladder (91). The top of the top cover (10) is provided with an upper liquid channel (112), and the top of the top cover (10) is fixedly sealed with a sealing cover plate (113) that matches the upper liquid channel (112). The battery bracket (3) is fixedly connected with multiple connecting pipes (114). The lower liquid channel (111) is connected to the upper liquid channel (112) through the connecting pipes (114). Multiple support pipes (114) are fixedly inserted between the top cover (10) and the base (5) at a position outside the outer shell (1). 15), the top cover (10) and the base (5) are provided with frame-shaped cavities (116) at their inner outer edges, and each support tube (115) is connected to the two frame-shaped cavities (116). The upper liquid channel (112) and the lower liquid channel (111) are fixedly connected with multiple horizontal tubes (117) that are connected to the frame-shaped cavities (116) on the same side. The protective plate (7) and the pressing frame (92) are jointly equipped with the pressurizing drive assembly (12) of the compression elastic bladder (91). The upper liquid channel (112), the lower liquid channel (111), the connecting tube (114), the support tube (115), and the frame-shaped cavity (116) are also filled with buffer solution.

4. A lithium battery with self-protection function according to claim 3, characterized in that, The pressurization drive assembly (12) includes a mounting groove (121) on the top of the protective plate (7), and a pressure plate (122) is slidably connected inside the mounting groove (121). The pressure plate (122) is located below the elastic bladder (91). Multiple iron blocks (123) are fixedly inserted at the top outer edge of the pressure plate (122). Multiple electromagnetic blocks (124) corresponding to the positions of the iron blocks (123) are fixedly installed at the bottom of the pressing frame (92), and the electromagnetic blocks (124) are electrically connected to the control terminal of the BMS protection board (2).

5. A lithium battery with self-protection function according to claim 3, characterized in that, The outer wall of the support tube (115) is rotatably fitted with a stress relief sleeve (13), and the side walls of two adjacent stress relief sleeves (13) are in contact.

6. A lithium battery with self-protection function according to claim 3, characterized in that, A set of temperature probes (14) is fixed at the bottom of the sealing cover plate (113) inside the upper liquid tank (112). The BMS protection board (2) controls the electromagnetic block (124) to work according to the electrical signal fed back by the temperature probes (14).

7. A lithium battery with self-protection function according to claim 3, characterized in that, The support tube (115) is equipped with a one-way valve (15), and the buffer solution flows from the upper opening of the one-way valve (15) to the lower opening. The inlet end of each horizontal tube (117) located at the upper liquid channel (112) is lower than the upper opening of the connecting tube (114).

8. A lithium battery with self-protection function according to claim 5, characterized in that, The external interface of the BMS protection plate (2) is located on the side wall of the outer shell (1), and the support tube (115) and the unloading sleeve (13) are offset from the external interface of the BMS protection plate (2). The top cover (10) and the base (5) are rotatably connected to a rotating roller (16) at opposite ends. The rotating roller (16) is located on the upper and lower sides of the external interface of the BMS protection plate (2). The rotating roller (16) is in contact with the side wall of the unloading sleeve (13) on the same side, and the side walls of two adjacent rotating rollers (16) on the same side are in contact.

Images