Universal rechargeable battery formed by adopting lithium-ion battery and control method thereof

Abstract

The invention provides a universal rechargeable battery formed by adopting a lithium-ion battery and a control method thereof. The universal rechargeable battery comprises an external packing casing, as well as a charging / discharging controller, a positive electrode welding piece, the lithium-ion battery and a negative electrode end cover which are sequentially assembled in the external packing casing in a press fit manner, wherein the charging / discharging controller comprises a charging / discharging controller casing as well as a charging / discharging control circuit welding body and a charging / discharging controller support, which are arranged in the charging / discharging controller casing; a lithium-ion battery charging / discharging control circuit is welded on a charging / discharging control circuit welding body; the lithium-ion battery charging / discharging control circuit comprises a lithium-ion battery charging control circuit welded on a circuit board, electrically connected with the lithium-ion battery and the positive electrode end cover respectively and further electrically connected with the negative electrode end cover via the charging / discharging controller casing and the external packing casing, a lithium-ion battery detection and control circuit, and a DC-DC step-down voltage stabilizing discharging circuit.

Description

technical field [0001] The invention relates to the technical field of secondary batteries or electronic power sources, in particular to a general-purpose rechargeable battery composed of a lithium-ion battery and a control method. Background technique [0002] Lithium-ion secondary batteries (hereinafter referred to as lithium-ion batteries) have the advantages of large specific energy, fast charging and discharging, long cycle life, small self-discharge, no pollution, no memory effect, etc., and are currently replacing general-purpose primary batteries and nickel metal hydride Rechargeable batteries are ideal secondary batteries. However, the output voltage of the existing lithium-ion batteries is relatively high, and the output voltage varies with the positive electrode system used. The commercialized lithium-ion batteries currently have a nominal voltage of 3.2V to 3.8V, and with lithium With the development of ion battery technology, the nominal voltage of lithium-ion ...

AI Technical Summary

Problems solved by technology

There are the following technical performance defects, one: the forward conduction voltage drop of the diode will vary with the operating current and temperature during charging, which reduces the detection and charging control accuracy of the charging control circuit for lithium-ion batteries. When the conduction voltage drop is high, there will be a problem that the lithium-ion battery cannot be fully charged. When the forward conduction voltage drop of the diode is low, the lithium-ion battery is prone to overcharging, which reduces the charging performance and safety of the lithium-ion battery; second: Since the charging circuit is connected to the isolation diode, the charging input voltage of the rechargeable battery is raised. Since the charging upper limit voltage of the existing cobalt-lithium system lithium-ion battery has reached 4.35V and will increase in the future, if the nominal voltage is 5V± 0.25V existing general-purpose lithium-ion battery charging adapter or computer USB interface to charge the rechargeable battery, even if a Schottky device with a low forward conduction voltage drop is used, the charging input voltage lower limit and the isolation diode conduction voltage drop upper limit state However, there is still the problem that the lithium-ion battery cannot be fully charged. Although a boost circuit can be used in the external charging device to solve this problem, it will cause problems such as an increase in the cost of the charging device, and a decrease in efficiency and reliability; third: the external temperature The sensing circuit can only indirectly detect the temperature of the lithium-ion battery through the outer packaging shell or electrodes of the rechargeable battery, which reduces the detection accuracy of the charging temperature of the lithium-ion battery, and causes the rechargeable battery to have the problem that the lithium-ion battery is overheated and the cycle life and safety are reduced. question

[0010] Second, rechargeable batteries do not have lithium-ion battery discharge overheat protection

[0011] There is no lithium-ion battery temperature sensing and control circuit installed inside the rechargeable battery, so that the rechargeable battery does not have the overheat protection function during the discharge process of the lithium-ion battery. Risk of upper operating temperature, thus reducing the cycle life and safety of Li-ion batteries

[0012] Third, the structure and assembly process of the charge and discharge controller are complex

In addition, the elastic negative electrode is a movable part, and its structure occupies a large internal space of the charge-discharge controller, and makes it difficult to realize the sealing of the charge-discharge controller

As a result, the charge and discharge controller has a large volume, complex and difficult manufacturing process, is not conducive to automatic mass production assembly, and cannot achieve waterproof sealing. Prone to circuit failure problems

[0014] Fourth, the connection reliability between the charge and discharge controller and the positive electrode of the lithium-ion battery is poor

[0015] The charge-discharge controller for R20 rechargeable battery and R14 rechargeable battery is connected to the positive electrode of the lithium-ion battery by elastic crimping. Since the contact surface between the electrodes is limited by space, it is easy to cause a shock when the rechargeable battery is charged and discharged with a large current. spot ablation

Contact ablation and oxidation will cause the internal resistance of the rechargeable battery system to increase, and the heat generated during charging and discharging will increase the operating temperature of the rechargeable battery. In severe cases, an open circuit will cause the rechargeable battery to fail.

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