Cylindrical lithium battery positive and negative electrode connecting device with built-in BMS (Battery Management System) board

Abstract

The utility model relates to the technical field of cylindrical lithium batteries, in particular to a cylindrical lithium battery anode and cathode connecting device with a built-in BMS (Battery Management System) board, which comprises a lithium battery main body, a BMS component arranged in the lithium battery main body and a connecting device, the BMS assembly comprises a cover cap arranged at the top end of the conductive shell and a BMS mainboard arranged in the cover cap and used for detecting a roll core group, the roll core group comprises a positive roll core and a negative roll core which are alternately wound, a positive tab is arranged at one end, close to the BMS mainboard, of the positive roll core, a negative tab is arranged at one end, close to the BMS mainboard, of the negative roll core, and the positive tab is connected with the negative tab. The connecting device comprises a first conductive terminal of which one end is connected with the BMS mainboard and the other end is connected with the positive tab, and a second conductive terminal of which one end is connected with the BMS mainboard and the other end is connected with the negative tab. According to the utility model, the positive and negative tabs can be directly connected with the BMS mainboard, and the real-time monitoring of the battery state by the BMS assembly is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of cylindrical lithium batteries, in particular to a positive and negative electrode connecting device of a cylindrical lithium battery with a built-in BMS board. Background Art

[0002] Cylindrical lithium battery is a common lithium-ion battery design with a cylindrical shape, usually composed of a positive electrode, a negative electrode, an electrolyte, a separator and a shell. It is widely used in portable electronic products, power tools, electric vehicles and other fields. Due to its high energy density and reliability, it has become the main energy source for many modern devices.

[0003] The applicant has applied for a utility model patent with application number CN202321813486.1 and the name of "Cylindrical lithium battery cap negative electrode side connection device with built-in BMS board", which includes an outer shell, which is an overall cylindrical structure, and the outer shell is set to steel material; a battery core is fixedly installed inside the outer shell, and the battery core is set to a battery material with a lithium alloy material as the negative electrode; the upper end of the outer shell is fixedly provided with a top cap with an inward-shaped structure, and a plastic bracket is installed inside the top cap. The negative electrode side connection device of the cylindrical lithium battery cap with a built-in BMS board adopts a new structural design to improve the performance and safety of lithium batteries. Improve system stability, reduce failure rate, save design costs, improve production efficiency, optimize equipment structure, and improve internal space utilization, and replace the traditional welding connection method, thereby improving the safety and reliability of the battery, improving the efficiency of battery mass production, and realizing automated production.

[0004] However, in the above structure, the built-in BMS board is only connected to the negative electrode, and there is a lack of direct positive electrode monitoring and protection measures, which results in reduced response speed and accuracy of the BMS when detecting safety hazards such as overcharging and short circuits. Utility Model Content

[0005] In order to solve the problems in the above-mentioned background technology, the utility model provides a positive and negative electrode connection device of a cylindrical lithium battery with a built-in BMS board.

[0006] The utility model solves the technical problem by adopting the following scheme: a positive and negative electrode connection device of a cylindrical lithium battery with a built-in BMS board, comprising a lithium battery body, a BMS component arranged in the lithium battery body and a connection device, wherein the lithium battery body comprises a core group and a conductive shell wrapped outside the core group, the BMS component comprises a cap arranged at the top of the conductive shell and a BMS main board arranged in the cap for detecting the core group, the core group comprises a positive electrode core and a negative electrode core wound alternately, the positive electrode core is provided with a positive electrode ear at one end close to the BMS main board, the negative electrode core is provided with a negative electrode ear at one end close to the BMS main board, the connection device comprises a first conductive terminal connected to the BMS main board at one end and connected to the positive electrode ear at the other end, and a second conductive terminal connected to the BMS main board at one end and connected to the negative electrode ear at the other end.

[0007] By adopting the above technical solution, the positive and negative electrode ears are both set on the top of the winding core, and the BMS main board is connected to the positive and negative electrode ears through the additional first and second conductive terminals, ensuring that the BMS components can monitor the positive and negative electrode status of the battery in real time and accurately.

[0008] Furthermore, a conductive portion is provided on the periphery of the end surface of the BMS mainboard, and the conductive portion is electrically connected to the second conductive terminal. A flange portion is provided on the top of the conductive shell and abuts against the conductive portion for conducting the negative electrode.

[0009] By adopting the above technical solution, the external conductive shell is used as the negative electrode.

[0010] Furthermore, the cap includes a plastic bracket embedded in the top of the conductive shell for accommodating and fixing the BMS mainboard and a positive conductive column installed on the BMS mainboard and electrically connected to the first conductive terminal.

[0011] By adopting the above technical solutions, the plastic bracket provides a stable installation platform for the BMS motherboard and protects sensitive electronic components from damage, and the positive conductive column can be used as the positive electrode of the battery.

[0012] Furthermore, the BMS component also includes a connection cover embedded in the plastic bracket, and the connection cover and the BMS mainboard are jointly embedded in the plastic bracket to form a sealed fixed structure, and the first conductive terminal and the second conductive terminal both penetrate and are fixed to the connection cover and connected to the BMS mainboard.

[0013] By adopting the above technical solutions, the internal electronic components can be effectively isolated from the external environment and the physical stability of the BMS components can be enhanced.

[0014] Furthermore, two through holes are provided at the bottom of the connecting cover, and the first conductive terminal and the second conductive terminal both include a main body installed in the BMS mainboard through the through hole and a limiting portion integrally formed at the bottom of the main body and used for welding and fixing the positive electrode ear and the negative electrode ear, the area of ​​the limiting portion is larger than the through hole, and a positioning ring is further provided above the limiting portion, and the limiting portion and the positioning ring jointly clamp the bottom of the connecting cover to fix it.

[0015] By adopting the above technical solution, the position of the conductive terminal is fixed to prevent it from loosening during use.

[0016] Furthermore, the connection cover is provided with a pressure relief portion at a central position on one side of the core group, and the end surface of the pressure relief portion is provided with a cross indentation for automatically rupturing when the internal pressure of the battery abnormally rises to a preset threshold, and at least one air leakage hole is provided on the end surface of the BMS main board.

[0017] By adopting the above technical solution, when the battery cell encounters an abnormality, resulting in an increase in internal pressure, and the internal pressure increases to a dangerous threshold, the thin part of the pressure relief part will rupture first, and the pressure relief hole will discharge excess internal gas to prevent an explosion.

[0018] In summary, the beneficial effects of the utility model are as follows: the utility model realizes real-time and accurate monitoring of the battery status by setting both the positive and negative tabs at the top of the winding core, and directly connects the positive and negative tabs to the BMS mainboard by adding the first conductive terminal and the second conductive terminal, thereby ensuring a rapid response to abnormal conditions such as overcharge, overdischarge, and short circuit. And by connecting the pressure relief part at the bottom of the cover and the mainboard vent hole, when the internal pressure of the battery cell increases abnormally, when the internal pressure increases to a dangerous threshold, the thin part of the pressure relief part will rupture first, and the pressure relief hole will discharge excessive internal gas to prevent explosion.

[0019] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structural decomposition of this embodiment;

[0021] Figure 2 is a cross-sectional view of this embodiment;

[0022] Figure 3 This is a schematic diagram of the bottom of the connection cover of this embodiment.

[0023] In the figure: 1. lithium battery body; 11. winding core group; 111. positive electrode winding core; 112. positive electrode ear; 113; negative electrode winding core; 114. negative electrode ear; 12. conductive shell; 121. flange portion; 2. BMS component; 21. cap; 211. plastic bracket; 212. positive electrode conductive column; 22. BMS main board; 221. conductive portion; 222. vent hole; 23. connecting cover; 231. through hole; 232. pressure relief portion; 233. cross indentation; 3. connecting device; 31. first conductive terminal; 32. second conductive terminal; 4. main body; 5. limit portion; 6. positioning ring. DETAILED DESCRIPTION

[0024] In order to make the content of the utility model more clearly understood, the utility model is further described below based on specific embodiments in combination with the accompanying drawings.

[0025] It should be noted that the terms "center", "upper", "lower", "front", "back", "left", "right", "inner", "outer" and the like used herein to indicate directions or positional relationships are based on directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. Unless otherwise specified, "plurality" means two or more.

[0026] Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral 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, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood by specific circumstances.

[0027] like Figure 1 to Figure 2As shown, a cylindrical lithium battery positive and negative electrode connection device 3 with a built-in BMS board includes a lithium battery body 1, a BMS component 2 arranged in the lithium battery body 1, and a connection device 3. The lithium battery body 1 includes a core group 11 and a conductive shell 12 wrapped outside the core group 11. The BMS component 2 of this embodiment includes a cap 21 arranged at the top of the conductive shell 12 and a BMS main board 22 arranged in the cap 21 for detecting the core group 11, and the core group 11 includes alternating The positive electrode core 111 and the negative electrode core are wound, and the positive electrode core 111 is provided with a positive electrode ear 112 at one end close to the BMS main board 22, and the negative electrode core is provided with a negative electrode ear 113 at one end close to the BMS main board 22; the negative electrode core; 114, the connecting device 3 includes a first conductive terminal 31 connected to the BMS main board 22 at one end and the positive electrode ear 112 at the other end, and a second conductive terminal 32 connected to the BMS main board 22 at one end and the negative electrode ear 113 at the other end; the negative electrode core; 114.

[0028] The positive electrode ear 112 of this embodiment is an extension of the positive electrode core 111 (usually an aluminum foil coated with a positive electrode active material) and provides a conductive path from the positive electrode material to the external circuit. The negative electrode ear 113; negative electrode core; 114 is an extension of the negative electrode core (copper foil coated with a negative electrode active material) and provides a conductive path from the positive electrode material to the external circuit. Both are arranged on the top and the core is welded and fixed in this embodiment, and the first and second conductive terminals 32 are added inside the lithium battery body 1 to connect the BMS motherboard 22 with the positive and negative electrode ears 113; negative electrode core; 114, ensuring that the BMS component 2 can monitor the positive and negative electrode status of the battery in real time and accurately, including key parameters such as voltage and current, which is crucial for preventing potential risks such as overcharging, over-discharging, and short circuit, and significantly enhances the safety performance of the battery.

[0029] like Figure 1 As shown, in this embodiment, a conductive portion 221 is provided at the periphery of the end surface of the BMS main board 22, and the conductive portion 221 is electrically connected to the second conductive terminal 32, and a flange portion 121 is provided at the top of the conductive shell 12 and abuts against the conductive portion 221 for conducting the negative electrode. The conductive portion 221 and the second conductive terminal 32 are directly electrically connected through the wiring on the BMS main board 22, and the conductive shell 12 becomes the negative electrode.

[0030] like Figure 1As shown, the cap 21 of this embodiment includes a plastic bracket 211 embedded in the top of the conductive housing 12 for accommodating and fixing the BMS mainboard 22 and a positive conductive column 212 installed on the BMS mainboard 22 and electrically connected to the first conductive terminal 31. The plastic bracket 211 not only provides a stable installation platform for the BMS mainboard 22, but also can effectively absorb external impacts and protect sensitive electronic components from damage, thereby improving the mechanical stability of the BMS system. By directly installing the positive conductive column 212 on the BMS mainboard 22 and connecting it to the first conductive terminal 31, the positive conductive column 212 is used as the positive electrode of the battery.

[0031] like Figure 2 As shown, the BMS component 2 of this embodiment further includes a connection cover 23 embedded in the plastic bracket 211, and the connection cover 23 and the BMS main board 22 are embedded in the plastic bracket 211 together to form a sealed fixed structure, and the first conductive terminal 31 and the second conductive terminal 32 are both penetrated and fixed to the connection cover 23 and the BMS main board 22. The sealed fixed structure formed by the connection cover 23, the BMS main board 22 and the plastic bracket 211 effectively isolates the external environment from the internal electronic components, and enhances the physical stability of the BMS component 2, preventing the internal components from loosening or being damaged due to vibration during the use or transportation of the battery. Specifically, two through holes 231 are provided at the bottom of the connection cover 23, and the first conductive terminal 31 and the second conductive terminal 32 both include a main body 4 installed in the BMS main board 22 through the through hole 231 and a limiting portion 5 integrally formed at the bottom of the main body 4 and used to be fixed with the positive ear 112 and the negative ear 113; the negative electrode winding core; 114 by spot welding, and the area of ​​the limiting portion 5 is larger than the through hole 231, and a positioning ring 6 is also provided above the limiting portion 5, and the limiting portion 5 and the positioning ring 6 jointly clamp the bottom of the connection cover 23 to fix it, which can clamp the position of the fixed conductive terminal to prevent it from loosening during use.

[0032] like Figure 3 As shown, the connection cover 23 of this embodiment is provided with a pressure relief portion 232 at the central position of one side of the winding core group 11, and the end face of the pressure relief portion 232 is provided with a cross indentation 233 for automatically rupturing when the internal pressure of the battery abnormally rises to a preset threshold, and at least one air release hole 222 is provided on the end face of the BMS main board 22. The design of the pressure relief portion 232 and the cross indentation 233, which are thinner than other positions of the bottom of the cover, provides a passive safety protection mechanism for the battery. When gas accumulates inside the battery due to an abnormality (such as overcharging, internal short circuit), and the pressure exceeds the set safety threshold, the cross indentation 233 automatically ruptures as a weak point, and the excess pressure can be quickly released through the upper pressure relief hole, effectively preventing the battery from swelling or exploding, and significantly improving the safety of battery use.

[0033] In summary, the beneficial effects of this embodiment are as follows: this embodiment ensures the real-time monitoring of the battery status by the BMS component 2 by directly integrating the positive and negative electrode connection structure on the BMS mainboard 22, effectively preventing risks such as overcharging, overdischarging, and short circuit, and significantly improving the safety performance of the battery. At the same time, the sealing and fixing structure formed by the connection cover 23, the BMS mainboard 22, and the plastic bracket 211, as well as the design of the pressure relief part 232 and the air vent 222, provide a double safety guarantee for the battery, can effectively deal with abnormal internal pressure, prevent battery damage, and further consolidate the stability and safety of the battery.

[0034] The embodiments described above are only preferred implementation modes of the present utility model and cannot be used to limit the protection scope of the present utility model. Any non-substantial changes and modifications made by technicians in this field on the basis of the utility model shall fall within the protection scope of the present utility model.

Claims

1. A positive and negative electrode connection device for a cylindrical lithium battery with a built-in BMS board, comprising a lithium battery body, a BMS component arranged in the lithium battery body, and a connection device, wherein the lithium battery body comprises a winding core group and a conductive shell wrapped outside the winding core group, characterized in that: The BMS component includes a cap arranged on the top of the conductive shell and a BMS mainboard arranged in the cap for detecting the core group, the core group includes a positive electrode core and a negative electrode core that are alternately wound, the positive electrode core is provided with a positive electrode ear at one end close to the BMS mainboard, and the negative electrode core is provided with a negative electrode ear at one end close to the BMS mainboard, and the connecting device includes a first conductive terminal with one end connected to the BMS mainboard and the other end connected to the positive electrode ear, and a second conductive terminal with one end connected to the BMS mainboard and the other end connected to the negative electrode ear.

2. A cylindrical lithium battery positive and negative electrode connection device with a built-in BMS board according to claim 1, characterized in that: A conductive part is arranged at the periphery of the end surface of the BMS main board, and the conductive part is electrically connected to the second conductive terminal. A flange part is arranged at the top end of the conductive shell and abuts against the conductive part for conducting the negative electrode.

3. A cylindrical lithium battery positive and negative electrode connection device with a built-in BMS board according to claim 2, characterized in that: The cap includes a plastic bracket embedded in the top of the conductive housing for accommodating and fixing the BMS mainboard and a positive conductive column installed on the BMS mainboard and electrically connected to the first conductive terminal.

4. A cylindrical lithium battery positive and negative electrode connection device with a built-in BMS board according to claim 3, characterized in that: The BMS component also includes a connection cover embedded in the plastic bracket. The connection cover and the BMS mainboard are embedded in the plastic bracket together to form a sealed fixed structure. The first conductive terminal and the second conductive terminal both penetrate and are fixed to the connection cover and connected to the BMS mainboard.

5. A cylindrical lithium battery positive and negative electrode connection device with a built-in BMS board according to claim 4, characterized in that: The bottom of the connection cover is provided with two through holes, and the first conductive terminal and the second conductive terminal both include a main body portion installed in the BMS mainboard through the through holes and a limiting portion integrally formed at the bottom of the main body portion and used for welding and fixing the positive electrode ear and the negative electrode ear, the area of ​​the limiting portion is larger than the through holes, and a positioning ring is further provided above the limiting portion, and the limiting portion and the positioning ring jointly clamp the bottom of the connection cover to form a fixation.

6. A cylindrical lithium battery positive and negative electrode connection device with a built-in BMS board according to claim 5, characterized in that: The connection cover is provided with a pressure relief portion at the central position of one side of the winding core group, and the end surface of the pressure relief portion is provided with a cross indentation for automatically rupturing when the internal pressure of the battery abnormally rises to a preset threshold value, and at least one air leakage hole is provided on the end surface of the BMS mainboard.

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