Lithium battery with protective circuit embedded inside battery cap

Abstract

The invention relates to a lithium battery with a protective circuit embedded inside battery capThe lithium battery comprises a battery group composed of a battery and the protective circuit, a protection board with the protective circuit is arranged below the battery cap, a MOS switch in the protective circuit with a protection board IC is arranged between the anode of the battery B+ and the anode of the whole battery group P+, and the cathode of the battery B- and the cathode of the whole battery group P- are connected with the same terminal; and the anode of the whole battery group P+ is connected with the battery cap, and the cathode of the whole battery group P- is connected with the inner side of the battery steel shell. The battery protective board in the invention is arranged below the cap of the battery group, the whole battery group has protection function, the battery group has no change in appearance after adding the protective board so as to change the condition that the appearance of the battery is changed after adding the protection system, and the battery group is artistic and can be directly combined in series or parallel connection, thus greatly reducing use requirement of a cylinder battery and expanding the application range of a cylinder lithium battery.

Description

technical field [0001] The invention relates to a lithium ion battery with a protection circuit, in particular to a lithium battery with the protection circuit built into the battery cap. Background technique [0002] The existing rechargeable cylindrical lithium-ion batteries are all single batteries without lithium-ion protection plates, and are usually used in industrial fields, such as digital products such as notebook computers and mobile DVDs. According to specific application requirements, Combining batteries in series and parallel, and adding corresponding protection circuits to make battery packs, which are used in specific electrical appliances, usually have a one-to-one correspondence with electrical appliances, and the versatility of the product is not strong. [0003] Due to the development of portable electronic products, the requirements for the use of high-capacity and reusable lithium batteries are becoming more and more extensive. Since the common cylindric...

AI Technical Summary

Problems solved by technology

[0006] 1. The appearance of the battery pack needs to change a lot: because the protective plates have a certain shape, these protective plates must have a certain volume. When the protective plate is installed on any position of the battery, the shape of the battery pack will definitely change.

[0007] 2. There is a hidden danger of insulation: because the protection board must introduce two signals, B+ and B-, usually the signals are connected to the battery case through a nickel belt. When the positive signal is connected to the protection board through the side of the battery case, the side of the battery The shell body is actually the negative pole of the battery, and there must be a potential difference between the two. Once a short circuit occurs here, it is actually a short circuit inside the battery. At this time, the protective plate has lost its protective effect, which will lead to potential safety hazards for the battery.

[0012] 1. Reduction of battery capacity: The size of cylindrical batteries is already a common standard. After the protective plate is placed in the lower part of the cavity of the battery case, the protective plate occupies the volume of the inner cavity of the steel shell, which will inevitably lead to effective The reduction in volume leads to a reduction in the volume of the active material of the battery that can be placed, which directly leads to a decrease in the capacity of the battery and shortens the power supply time of the battery for supporting equipment.

[0013] 2. The possibility of the protective plate being corroded: In order to protect some other metals on the protective plate from being corroded by the electrolyte, the protective plate must be sealed and isolated with special materials, which will increase the cost and leave hidden dangers of poor sealing; Moreover, when the electrolyte corrodes other metal impurities, it will bring other unpredictable safety hazards to the battery.

[0014] 3. There is a hidden danger in the insulation of the positive electrode lead of the battery: This is a bigger hidden danger. Because the signal of the positive electrode of a battery is required by the protection board, the usual design is to use an aluminum-nickel composite strip, from the slit between the steel shell and the battery core, It is connected from the top of the cell to the bottom of the cell, which leaves the greatest safety hazard. Once the battery is short-circuited internally, the protection board will no longer work

It is difficult to weld the battery negative electrode: because the output negative electrode of the battery must be the steel shell of the battery, usually the steel shell needs to be welded, and there is a protective plate in the middle, which will cause welding difficulties

[0015] 4. Difficulty in battery assembly and processing: In order to reduce the internal resistance of the battery, lithium batteries usually weld the nickel strip drawn from the negative electrode and the bottom of the steel case of the battery together. Since a protective plate is added to the steel case, it will undoubtedly lead to welding failure. difficulty

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