How to determine if a CRbattery has a short circuit?

To judge whether the CR disposable lithium manganese button battery is short-circuited, it can be determined by the appearance, Voltage, temperature, internal resistance, use five types of rapid detection methods, which can be determined using simple practical means, and distinguish between three states of already occurring short circuit, microshort circuit, and suspected short circuit, taking into account simple determination in households and accurate determination in industrial / maintenance scenarios, as follows:

I. Quick appearance judgment (most intuitive, no tool required)

Initial screening with the naked eye / hand touch and suitable for most everyday scenarios

1. Shell deformation drum pack

Normal batteries are flat and perfect, and after a short circuit, the internal gas overall swells, the cathode depression / bulge, the edges warp, and the shell cracks in severe cases, which are the core characteristics of the short circuit.

2. Leaky fluid and traces of corrosion

The short-circuit high temperature caused the electrolyte to decompose and seep out, the shell appeared white crystals, brown / green rust spots, sticky stains, and liquid residue at the seal, indicating that a short circuit had occurred and the internal structure was damaged.

3. Shell discoloration / burning

The thermal heat of the short-circuit high current causes the outer shell to yellow, black, and carbonize, and in extreme cases there are overheated charred marks, and the metal touch points to black oxidation, which is obvious evidence of short circuit.

4. Temperature abnormality

When sitting / unused, it spontaneously flares, is warm (far exceeding the ambient temperature), and is noticeably hot when holding hands, which is a typical manifestation of short circuit (including microshort circuit); Normal battery sitting is consistent with room temperature, light load is only slightly warm.

II. Voltage detection (the most accurate and necessary for home use)

Testing with a multimeter (DC voltage range, 20 V range) is the core standard for determining short circuit

1. The open circuit voltage is severely low

The normal open voltage of the new battery is 3.0 ~ 3.4V, and ≥ 2.8V after storage;

After the short circuit, the voltage sag to 0 ~ 0.5V, after removing the load can not rise, directly determine the complete short circuit;

If the voltage is 1.0-2.5V and continues to slowly decline, it is mostly micro-short circuit / internal local short circuit.

2. The load voltage went to zero instantly

The battery is connected to a small load (such as LED small lamp beads), and the normal voltage is stable after a small drop; When the short circuit voltage drops to 0V, the load has no response, which can be diagnosed.

III. Internal resistance and current detection (maintenance / industrial scenario)

Need a professional internal resistor / universal gauge current level to accurately determine hidden short circuit

1. An abnormally high increase in internal resistance

Normal battery internal resistance is tens to hundreds of milliohms; After a short circuit, the electrode / diaphragm is damaged, and the internal resistance rises to thousands of euros or even infinite, without conductive capacity.

2. Short circuit current is abnormal

Normal battery instantaneous short-circuit current ≥ 250 ~ 300 mA; The current after a short circuit is almost 0;The standby leakage current is much larger than the standard value (normal ≤ 1μA).

IV. Device performance judgment (assisted judgment when no tool is available)

1. The device failed instantaneously

After installing the new battery, the clock, remote control, car keys, etc. immediately do not work, and after turning on the machine, it is probable that the battery short circuits.

2. Abnormal power consumption / self-discharge super fast

The battery goes out within a few days after being installed, and can normally be used for months to 1 year, which is typical of internal micro short circuit (slight damage to the diaphragm, impurities conduction of electricity).

3. Heat / Corrosion of equipment

The battery barn heat, contact corrosion, and circuit board discoloration are mostly caused by short circuit leakage + heat of the battery.

V. Criteria for determining different short circuit states

Status Core criteria

Complete external short circuit voltage 0 ~ 0.5V, shell bulging / leaking / hot, no current output

A complete internal short circuit - a sudden voltage drop, an infinite internal resistance, possibly no obvious damage to the appearance but spontaneous heat -

Microshort circuit (hidden) The voltage slowly decreases, self-discharge is super fast, mildly warm, and the appearance is basically normal

Suspected short circuit (to be investigated) voltage 2.0 ~ 2.8V, no bulge leakage but fast power consumption, slight fever

VI. PROHIBITED OPERATIONS AND PRECAUTIONS

1. It is strictly forbidden to deliberately short-circuit the positive and negative electrodes of the battery for testing, which will cause the risk of heat, fluid leakage and cracking;

2. Batteries that are determined to have a short circuit should be discontinued immediately, recycled separately, and not continued to use or put into the fire / heat.

3.Distinguish between "dead battery" and "short circuit": no battery voltage ≥ 2.0V, no heat leakage, short circuit battery voltage is very low + abnormal heat / deformation;

4. When multiple pieces are stored, avoid contact between the positive and negative electrodes of the battery and metal items to prevent an accidental short circuit.

VII. Quick Checkup Steps (Home Minimalist Edition)

1.Touch temperature: whether sitting still is hot → if it is short circuit;

2.Look at the appearance: whether there is a drum pack, leakage, discoloration → if so, a short circuit;

3.Measuring voltage: < 2.0V and can not rise → basic short-circuit determination;

4.Test equipment: fails seconds after loading / consumes electricity at high speed → Diagnoses a short circuit after eliminating equipment problems.