Cylindrical lithium battery cap with built-in BMS (Battery Management System) board and cylindrical lithium battery with cap

Abstract

The utility model aims to provide the cylindrical lithium battery cap with the built-in BMS board and the cylindrical lithium battery with the cap, which have the characteristics of compact and reasonable structure, convenience in production and manufacture and miniaturization, and can reduce the influence of battery cell capacity reduction caused by the need of installing the BMS board to the maximum extent.

Description

Technical Field

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

[0002] Cylindrical lithium battery is a common secondary battery, also called lithium-ion battery. It consists of a cylindrical container, which contains components such as positive electrode, negative electrode and electrolyte. The battery cap is the component structure of the cylindrical lithium battery, which performs the sealing process on the top.

[0003] At present, there are cylindrical lithium batteries without BMS system and with BMS system on the market. Battery Management System (BMS) is an important part of modern battery technology, especially in electric vehicles and renewable energy storage systems. The main function of BMS is to ensure the safety and stability of battery packs and improve energy efficiency.

[0004] Since the dimensions of lithium batteries are standardized, such as No. 5 and No. 7 batteries, if a cylindrical lithium battery needs to be equipped with a BMS system, the lithium battery cell needs to be reduced in size. After making independent sealed battery cells and independent BMS systems, the two need to be installed in the battery housing and electrically connected. For this type of cylindrical lithium battery with a BMS system, the BMS system is installed separately from the battery cell, resulting in a greatly reduced battery cell, reduced battery capacity, increased overall battery weight, high manufacturing costs, and complex installation during production and processing, which limits the scope of battery application and performance.

[0005] Therefore, how to make a miniaturized rechargeable cylindrical lithium battery with a built-in BMS board has become a technical challenge in this field.

[0006] The applicant has applied for application number CN202310996046.2 , a utility model patent named "A cylindrical lithium battery cap with built-in BMS board", which includes: a steel shell; a cap with a BMS board, connected to the inner side of the steel shell; a metal conductive ring, the lower end of which is connected to the inside of the cap with a BMS board; a positive conductive metal cover, the lower end of which is connected to the inside of the metal conductive ring; a PCBA board, connected to the upper outer edge of the positive conductive metal cover; the middle part of the lower end of the PCBA board extends to the middle part of the positive conductive metal cover, and the PCBA board includes a BMS chip, a power management chip, a battery control chip, a display chip, and a multi-way protector; the upper outer edge of the PCBA board is connected to a negative hardware ring; the opening of the steel shell is rolled inward in a whole circle and contacts the negative hardware ring to conduct the negative electrode; the inner side wall of the negative hardware ring is connected to the positive plastic cover, there is damping between the two, and the middle part of the positive plastic cover is an open hole structure, and fits with the external positive hardware column. The utility model solves the cap structure of the existing cylindrical lithium battery. In order to meet the use requirements, the BMS used for monitoring is built-in to simplify the installation steps.

[0007] However, in the above solution, due to the structural setting of the metal conductive ring, the existence of the negative electrode hardware ring, and the existence of the positive electrode plastic cover, the structure of the entire cap is still not the most compact and there is still room for improvement. Utility Model Content

[0008] The first purpose of the present invention is to provide a cylindrical lithium battery cap with a built-in BMS board, which is particularly suitable for small cylindrical lithium batteries such as No. 7 batteries. It has the advantages of compact and reasonable structure, easy production and manufacturing, and is conducive to the production of miniaturized cylindrical lithium batteries with built-in BMS boards. The cylindrical lithium battery cap with a built-in BMS board described in the present invention can minimize the impact of the reduction in battery cell capacity due to the need to install a BMS board.

[0009] A cylindrical lithium battery cap with a built-in BMS board, comprising a capping mechanism, wherein the capping mechanism comprises a capping shell, a positive electrode conductive metal cover, a BMS component, and a metal conductive ring for protecting the BMS component;

[0010] The cap housing is used to be connected to the inner side of the steel shell of the cylindrical lithium battery;

[0011] The positive electrode conductive metal cover is located in the cap housing and is used to be electrically connected to the positive electrode of the lithium battery cell;

[0012] The BMS assembly includes a BMS main board and a positive electrode insulating cover. The BMS main board is provided with a number of electronic components forming a BMS management system. The positive electrode insulating cover is arranged toward the positive electrode side of the cylindrical lithium battery and is sealed with the cap housing and the steel shell of the cylindrical lithium battery. The main board and the positive electrode insulating cover are integrally formed or separately arranged.

[0013] The positive electrode insulating cover is located above the positive electrode conductive metal cover and faces the positive electrode of the battery. The positive electrode insulating cover is sealed with the cap housing, and the BMS assembly is electrically connected to the steel shell.

[0014] The BMS main board and the metal conductive ring are both located between the positive electrode conductive metal cover and the positive electrode insulating cover;

[0015] The positive electrode conductive metal cover includes a main body with a groove and a flange portion integrally formed with the main body; the electronic components on the BMS main board are arranged toward the groove; and the metal conductive ring is abutted and connected between the flange portion and the positive electrode insulating cover portion.

[0016] Preferably, an embossed portion is provided on a side of the flange portion facing the positive electrode insulating cover portion.

[0017] Preferably, the positive electrode conductive metal cover is sealedly connected to the metal conductive ring and the cap shell.

[0018] Preferably, an explosion-proof pressure relief portion is provided at the central position of the positive conductive metal cover facing the positive electrode side of the battery cell. The thickness of the explosion-proof pressure relief portion is thinner than the thickness at other positions of the positive conductive metal cover, and when the internal pressure of the battery cell exceeds a threshold value, the explosion-proof pressure relief portion will prevent the internal pressure of the battery from being too high and exploding.

[0019] Preferably, the BMS main board part and the positive electrode insulating cover part are provided with slots communicating with the external air, and when the explosion-proof pressure relief part explodes, the explosion-proof pressure relief part is connected to the slots.

[0020] By adopting the above technical solution, the structural setting method of the metal conductive ring is improved, and at the same time, the negative electrode hardware ring is omitted, making the structure of the entire cap more compact, which can further increase the capacity of the battery cell. In addition, the main board part and the positive electrode insulating cover part are integrally formed or separately arranged, and the arrangement method is more flexible. When the two are integrally formed, the volume of the cap is further reduced. When the two are separately arranged, the positive electrode insulating cover part can also be made thinner than the positive electrode plastic cover in the prior art, and fit more closely with the main board part. At the same time, because the positive electrode conductive metal cover is made of soft aluminum material, and the structure inside the No. 7 lithium battery is too small, it is necessary to add a circle of support to raise the space to increase the electronic parts and conduct electricity at the same time, so a positive electrode metal conductive ring is required.

[0021] There is an explosion-proof pressure relief part on the positive conductive metal cover. When the internal pressure of the battery cell is abnormally high and exceeds the threshold, the metal of the explosion-proof pressure relief part is thin and will rupture first to prevent the internal pressure from being too high and exploding. There are one or more slots on the BMS motherboard that lead directly to the outside. After the explosion-proof pressure relief part ruptures, the high-pressure gas is discharged from this hole.

[0022] Therefore, the cap of the utility model has a more reasonable structure, uses fewer parts, has a lower production cost, is simpler to manufacture, and is more compact, so that the lithium battery using the cap of the structure can have a larger battery capacity.

[0023] The second purpose of the utility model is to provide a cylindrical lithium battery, wherein the cylindrical lithium battery cap with a BMS board inside the cylindrical lithium battery cap has the advantages of a miniaturized cylindrical lithium battery with a built-in BMS board, minimizing the impact of the reduction in battery cell capacity due to the need to install a BMS board, and has a simple and compact structure, good sealing, and the battery is practical, safe and reliable.

[0024] A cylindrical lithium battery comprises a battery insulating shell, a steel shell arranged inside the battery insulating shell, and a battery cell arranged inside the steel shell, wherein the negative electrode of the battery cell is electrically connected to the steel shell, the cylindrical lithium battery cap with the above-mentioned built-in BMS board is arranged inside the steel shell, the positive electrode of the battery cell is electrically connected to the positive conductive metal cover, and a circle of soldering part is arranged on the side of the positive insulating cover part facing the positive conductive column of the battery, and the soldering part is electrically connected to the steel shell.

[0025] Preferably, the main board portion and the positive electrode insulating cover portion (132) are provided with formation holes which are connected to each other and used when the lithium battery is formed, so as to allow the lithium battery to be charged and discharged to activate the lithium battery.

[0026] By adopting the above technical scheme and a more reasonable cap structure, which is particularly suitable for miniature lithium batteries of 1.5V and other different fixed voltages of No. 7 batteries, the solder part is electrically connected to the steel shell, and the positive conductive metal cover is electrically connected to the positive electrode of the battery cell, which forms an internal circuit loop for outputting the 3.6V of the internal battery cell to different voltages such as 1.2V, 1.5V, and 9V. The resulting lithium battery has higher sealing performance, more guaranteed explosion-proof effect, and a larger battery capacity than the original cylindrical lithium battery with a BMS board. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a cross-sectional view of a cylindrical lithium battery (the battery insulation shell is omitted), and a cylindrical lithium battery cap with a built-in BMS board as described in the utility model;

[0028] Figure 2 for Figure 1 A magnified view of part B;

[0029] Figure 3 Schematic diagram of the disassembly of a cylindrical lithium battery Figure 1 (battery insulation housing omitted), a cylindrical lithium battery cap with a built-in BMS board as described in the utility model;

[0030] Figure 4 Schematic diagram of the disassembly of a cylindrical lithium battery Figure 1 (battery insulation housing omitted), a cylindrical lithium battery cap with a built-in BMS board as described in the utility model;

[0031] 1. Capping mechanism; 11. Capping shell; 12. Positive conductive metal cover; 121. Main body; 122. Flanging; 1221. Embossed; 123. Explosion-proof pressure relief; 13. BMS assembly; 131. BMS main board; 132. Positive insulating cover; 1321. Soldering; 133. Electronic components; 134. Slots; 14. Metal conductive ring;

[0032] 21. Steel shell; 22. Battery cell; 221. Positive electrode of battery cell; 222. Negative electrode of battery cell. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1-4 The utility model is further described.

[0034] Embodiment 1

[0035] like Figure 1-4 As shown, a cylindrical lithium battery cap with a built-in BMS board includes a capping mechanism 1, wherein the capping mechanism 1 includes a capping shell 11, a positive conductive metal cover 12, a BMS component 13, and a metal conductive ring 14 for protecting the BMS component 13 (the positive conductive metal cover 12 is preferably made of soft aluminum material, which makes the positive conductive metal cover 12 soft. The space inside the No. 7 lithium battery is too small, so a circle of support and lifting space is needed to increase the placement space of electronic components, while ensuring the normal conductive function, so the positive metal conductive ring is provided);

[0036] The cap housing 11 is used to be connected to the inner side of the steel shell 21 of the cylindrical lithium battery;

[0037] The positive electrode conductive metal cover 12 is located in the cap shell 11, and is used to be electrically connected to the positive electrode 221 of the lithium battery cell. The positive electrode conductive metal cover 12 includes a main body 121 with a groove, and a flange 122 integrally formed with the main body 121; the positive electrode conductive metal cover 12 is provided with an explosion-proof pressure relief portion 123 at the central position of the positive electrode side of the battery cell, and the thickness of the explosion-proof pressure relief portion 123 is thinner than that of other positions of the positive electrode conductive metal cover 12, and when the internal pressure of the battery cell 22 exceeds a threshold value, the explosion-proof pressure relief portion 123 will prevent the internal pressure of the battery from being too high and exploding;

[0038] The BMS assembly 13 includes a BMS main board 131 and a positive electrode insulating cover 132. The BMS main board 131 is provided with a number of electronic components 133 forming a BMS management system. The positive electrode insulating cover 132 is arranged toward the positive electrode side of the cylindrical lithium battery and is sealed with the cap housing 11 and the steel shell 21 of the cylindrical lithium battery. The main board and the positive electrode insulating cover 132 are integrally formed or separately arranged.

[0039] The electronic components 133 on the BMS main board 131 are arranged toward one side of the groove; the metal conductive ring 14 is connected between the flange portion 122 and the positive electrode insulating cover portion 132; the BMS main board 131 and the positive electrode insulating cover portion 132 are provided with a slot 134 that communicates with the outside air. When the explosion-proof pressure relief portion 123 explodes, the explosion-proof pressure relief portion 123 is connected to the slot 134, and the high-pressure gas is discharged from the inside of the battery cell 22 to the positive electrode conductive metal cover 12 and then discharged from the slot 134;

[0040] The positive electrode insulating cover 132 is located above the positive electrode conductive metal cover 12 and is in contact with the flange 122. The positive electrode insulating cover 132 is sealed with the cap housing 11. The flange 122 is provided with an embossed portion 1221 on one side facing the positive electrode insulating cover 132. The raised surface of the embossed portion 1221 is in contact with the metal conductive ring 14. The embossed portion 1221 makes the contact between the positive electrode conductive metal cover 12 and the metal conductive ring 14 more stable, thereby ensuring the stability of the current conduction of the BMS component 13.

[0041] The BMS main board 131 and the metal conductive ring 14 are both located between the positive conductive metal cover 12 and the positive insulating cover 132. The positive insulating cover 132 is located above the positive conductive metal cover 12 and faces the positive electrode of the battery. The positive insulating cover 132 is sealed with the cap housing 11, and the BMS assembly 13 is electrically connected to the steel shell 21. More specifically, a circle of soldering part 1321 is provided on the side of the positive insulating cover 132 facing the positive conductive column of the battery, and the soldering part 1321 is electrically connected to the steel shell 21.

[0042] The positive electrode conductive metal cover 12 is sealedly connected to the metal conductive ring 14 and the cap shell 11 .

[0043] Embodiment 2

[0044] A cylindrical lithium battery comprises a battery insulating shell, a steel shell 21 arranged inside the battery insulating shell, and a battery cell 22 arranged inside the steel shell 21. The negative electrode 222 of the battery cell is electrically connected to the steel shell 21 so that the entire steel shell 21 becomes the negative electrode of the cylindrical lithium battery. The steel shell 21 is provided with a cylindrical lithium battery cap with a built-in BMS board as described in Example 1. The positive electrode 221 of the battery cell is electrically connected to the positive conductive metal cover 12. The positive insulating cover part 132 is provided with a circle of solder part 1321 on the side facing the positive conductive column of the battery, and the solder part 1321 is electrically connected to the steel shell 21.

[0045] It should be noted here that the steel shell is the negative electrode, and an inner ring of the steel shell is provided on the side of the steel shell facing the positive electrode of the battery. The inner ring of the steel shell is pressed together with the solder part. The solder part has a certain thickness, and tin is a soft metal. After the inner ring of the steel shell is pressed together, part of it is embedded in the solder part, achieving stable contact with the steel shell to meet the overcurrent requirements.

[0046] The voltage of the battery cell 22 itself is in the range of 3V-4.2V. The energy is small at low voltage and 4.2V after being fully charged. The solder part is electrically connected to the steel shell 21, and the positive conductive metal cover 12 is electrically connected to the positive electrode of the battery cell 22, which forms an internal circuit loop for outputting the 3.6V of the internal battery cell 22 into different voltages such as 1.2V, 1.5V, and 9V.

[0047] The above-mentioned implementation modes are only preferred implementation modes of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A cylindrical lithium battery cap with a built-in BMS board, comprising a capping mechanism (1), characterized in that: The capping mechanism (1) is composed of a capping shell (11), a positive electrode conductive metal cap (12), a BMS component (13), and a metal conductive ring (14) for protecting the BMS component (13); The cap housing (11) is used to be connected to the inner side of the steel shell (21) of the cylindrical lithium battery; The positive electrode conductive metal cover (12) is located inside the cap housing (11) and is used to be electrically connected to the positive electrode of the lithium battery cell (22); The BMS assembly (13) is composed of a BMS mainboard (131), a positive electrode insulating cover (132), and a plurality of electronic components (133) arranged on the BMS mainboard (131) and forming a BMS management system. The positive electrode insulating cover (132) is arranged toward the positive electrode side of the cylindrical lithium battery and forms a sealed connection with the cap housing (11) and the steel shell (21) of the cylindrical lithium battery. The BMS mainboard (131) and the positive electrode insulating cover (132) are integrally formed or separately arranged. The positive electrode insulating cover (132) is located above the positive electrode conductive metal cover (12) and faces the positive electrode of the battery. The positive electrode insulating cover (132) is sealed with the cap housing (11), and the BMS component (13) is electrically connected to the steel shell. The BMS mainboard portion (131) and the metal conductive ring (14) are both located between the positive electrode conductive metal cover (12) and the positive electrode insulating cover portion (132); The positive electrode conductive metal cover (12) comprises a main body (121) with a groove, and a flange portion (122) formed integrally with the main body (121); The electronic components (133) on the BMS mainboard part (131) are arranged toward one side of the groove; The metal conductive ring (14) is abuttingly connected between the flange portion (122) and the BMS mainboard portion (131).

2. The cylindrical lithium battery cap with built-in BMS board according to claim 1, characterized in that: An embossed portion (1221) is provided on one side of the flange portion (122) facing the positive electrode insulating cover portion (132).

3. The cylindrical lithium battery cap with built-in BMS board according to claim 2, characterized in that: The positive electrode conductive metal cover (12), the metal conductive ring (14) and the cap shell (11) are all sealed and connected.

4. The cylindrical lithium battery cap with built-in BMS board according to claim 2, characterized in that: An explosion-proof pressure relief portion (123) is provided at a central position of the positive electrode conductive metal cover (12) on the positive electrode side of the battery cell. The thickness of the explosion-proof pressure relief portion (123) is thinner than the thickness of other positions of the positive electrode conductive metal cover (12). When the internal pressure of the battery cell (22) exceeds a threshold value, the explosion-proof pressure relief portion (123) prevents the internal pressure of the battery from being too high and causing an explosion.

5. The cylindrical lithium battery cap with built-in BMS board according to claim 4, characterized in that: The BMS main board portion (131) and the positive electrode insulating cover portion (132) are provided with slots that communicate with the outside air, and when the explosion-proof pressure relief portion explodes, the explosion-proof pressure relief portion is connected to the slots.

6. A cylindrical lithium battery, comprising a battery insulating shell, a steel shell (21) disposed inside the battery insulating shell, and a battery cell (22) disposed inside the steel shell (21), wherein the negative electrode (222) of the battery cell is electrically connected to the steel shell (21), characterized in that: A cylindrical lithium battery cap with a built-in BMS board as described in any one of claims 1 to 5 is arranged in the steel shell (21), the positive electrode (221) of the battery cell is electrically connected to the positive conductive metal cover (12), and a circle of soldering part is arranged on the side of the positive insulating cover (132) facing the positive conductive column of the battery, and the soldering part is electrically connected to the steel shell (21).

7. The cylindrical lithium battery according to claim 6, characterized in that: The BMS main board part (131) and the positive electrode insulating cover part (132) are provided with formation holes which are connected to each other and used when the lithium battery is formed, so as to allow the lithium battery to be charged and discharged to activate the lithium battery.

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