CN201122837Y - A device for detecting overcurrent protection of a single string lithium-ion battery pack - Google Patents

Abstract

The utility model discloses a device for detecting overcurrent protection of a single-string lithium-ion battery pack. The utility model is realized through the following technical scheme, which is composed of a protection circuit module and a detection module. The protection circuit module is composed of a protection chip, a charging and discharging control coupling circuit, a MOSFET and a battery. The protection chip is connected to the battery through an isolation resistor to protect the The circuit module is provided with a test point, and a test line is drawn out from the test point; the detection module is a program-controlled electronic load connected to a test line, and the program-controlled electronic load is connected in parallel with a multimeter. The utility model provides a new detection device for detecting the overcurrent discharge current value, the device can accurately test the overcurrent discharge current value of the battery group without affecting the performance of the battery group, and ensures the safety of the battery group performance reliable. The device has the advantages of simple design, safe and reliable performance, convenient detection and wide application.

Description

A device for detecting overcurrent protection of a single string lithium-ion battery pack

technical field

The utility model relates to the field of electronic measurement and control devices, in particular to a device for detecting the overcurrent protection of a single-string lithium-ion battery pack.

Background technique

At present, a single-string lithium-ion battery pack usually consists of a single lithium-ion battery, an electronic protection circuit board, and a packaging case. Among them, the role of the protection circuit board is to prevent possible overcharging and over-discharging during use, and to prevent battery damage caused by abnormal conditions such as over-current discharge or short circuit; therefore, it is very important to protect the normal and stable performance of the circuit board. As a component, the protection circuit board has passed the incoming inspection before assembly. After the protection board is connected to the battery after assembly, it must also be tested for overcharge protection, over-discharge protection and over-current discharge performance.

The overcharge and overdischarge protection function of the lithium-ion battery pack is completed by the electronic components on the protection board. When charging, when the battery voltage of the battery pack is greater than or equal to the overcharge protection voltage, the output signal of the protection IC on the protection board turns off the charging MOSFET switch and stops charging. When the battery voltage is equal to or lower than the over-discharge protection voltage, the corresponding output will turn off the discharge MOSFET switch and stop discharging. The problem is, when the protection board is connected to the battery, if the overcharge protection and over discharge protection functions and voltage values of the protection board are to be detected, the input terminal of the IC for detecting the battery voltage on the protection board must meet the above conditions. It takes a long time to discharge to make the battery voltage reach the over-discharge protection voltage. On the other hand, it also takes a long time to charge the battery to make the battery voltage reach the over-charge protection voltage. This detection method is extremely unsuitable for large-scale production. Even for normal inspection, it is not suitable to actually discharge to over-discharge protection and charge to over-charge protection; because over-charging and over-discharging will have adverse effects on battery performance.

In actual production, over-discharge protection is usually not detected for single-string battery packs. Over-charge detection uses short-term high-current charging, and the battery voltage is raised to the over-charge protection voltage in a short time; Pack charging has the following disadvantages: Excessive charging current will affect the performance of the battery, which puts higher demands on the battery and measuring equipment, and must bear the impact of strong current, which will inevitably increase the manufacturing cost of the equipment. When detecting over-current discharge, a relatively high fixed constant current is usually used to check whether it is protected after the battery pack is connected. This test method has the following disadvantages: the over-current value cannot be accurately determined, and the set discharge The current is close to or reaches the upper limit of the protection board specification. When the actual overcurrent value of the battery pack is lower than the lower limit of the specification, it cannot be detected, and a missed detection occurs. As for the static self-consumption test, it is usually not tested now, so it is easy to miss the test of the battery pack with large self-discharge, and there are long-term hidden dangers.

Utility model content

The technical problem to be solved by the utility model is to provide a device for detecting the overcurrent protection of a single-string lithium-ion battery pack by overcoming the inaccurate shortcoming of the overcurrent test.

The utility model is a device for detecting the overcurrent protection of a single-string lithium-ion battery pack, which is realized through the following technical scheme, and is composed of a protection circuit module and a detection module. The protection circuit module is composed of a protection chip, a charging and discharging control coupling circuit, Composed of MOSFET and a battery, the protection chip is connected to the battery through an isolation resistor, the protection circuit module is provided with a test point, and a test line is drawn from the test point; the detection module is a program-controlled electronic load connected to a test line, and the program-controlled electronic load is connected in parallel with a multimeter.

The protection circuit module battery positive pole B+ of the utility model is connected to the Vdd terminal of the protection chip N1 through the isolation resistor R1, the negative pole of the battery is connected to the Vss terminal of the protection chip N1 and the MOSFET, and the MOSFET is connected to the D0 and C0 terminals of the protection chip.

The beneficial effects of the utility model are: a new detection device for detecting the overcurrent discharge current value is provided, the device can accurately test the overcurrent discharge current value of the battery pack without affecting the performance of the battery pack, ensuring The performance of the battery pack is safe and reliable. The device has the advantages of simple design, safe and reliable performance, convenient detection and wide application.

Description of drawings

Fig. 1 is the schematic diagram of circuit design of the utility model.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

The utility model is represented by a typical single-string protection circuit, and the measurement of other single-string protection circuits is the same, and can be expanded on the basis of this circuit diagram. As shown in Figure 1, the protection circuit module is composed of a protection chip, a charge-discharge control coupling circuit, a MOSFET and a battery. The battery positive pole B+ is connected to the Vdd end of the protection chip N1 through an isolation resistor R1, and the battery negative pole is connected to the Vdd end of the protection chip N1. The Vss terminal is connected to the MOSFET, and the MOSFET is connected to the D0 and C0 terminals of the protection chip. The above devices are combined with some resistive capacitor devices to form a protection circuit module. The protection circuit module is set with test points P+ and P-, and the test points lead to the test line; the detection module In the program-controlled electronic load connection test, the program-controlled electronic load is connected in parallel with the multimeter, as shown in Figure 1, turn on the electronic load switch and the multimeter switch, and set the current of the electronic load at a stable and appropriate speed. When the current value is equal to or greater than the overcurrent protection current , the MOSFET of the protection current is disconnected, and the multimeter for monitoring can show that the battery pack has been protected.

The detailed description of the above-mentioned reference example to the single-string lithium-ion battery pack overcharge, over-discharge protection voltage, over-current discharge and static self-consumption detection device is illustrative rather than limiting, so without departing from the utility model Changes and modifications under the overall concept should fall within the protection scope of the present utility model.

Claims (2)

1. device that detects the overcurrent protection of single string lithium ion battery group, it is characterized in that, form by protective circuit module and detection module, described protective circuit module by the protection chip, charge and discharge control coupling circuit, MOSFET and battery is formed, the protection chip is connected with battery through isolation resistance, the protective circuit module is provided with test point, draws p-wire by test point; Described detection module connects p-wire for the program-controlled electronic load, program-controlled electronic load universal instrument in parallel.

2. a kind of device that detects the overcurrent protection of single string lithium ion battery group according to claim 1; it is characterized in that; the anodal B+ of described protective circuit modular battery is connected with the Vdd end of protection chip N1 through isolation resistance R1; battery cathode is connected with Vss end and the MOSFET of protection chip N1, and MOSFET is connected with the C0 end with the D0 of protection chip.

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