The voltage of the aluminum shell cell after spot weld […]
The voltage of the aluminum shell cell after spot welding is lower than 3.7V, which is generally caused by the excessive spot welding current that causes the internal diaphragm of the cell to break down and short-circuit, causing the voltage to drop too fast.
is generally caused by the incorrect spot welding position. The correct spot welding position should be spot welding on the bottom or side with the mark "A" or "—". Spot welding is not allowed on the side and large side without marking. In addition, some spot-welded nickel tapes have poor weldability, so they must be spot welded with a large current, so that the internal high-temperature resistant tape can not work, resulting in internal short circuit of the battery.
Alkaline dry battery power failure after spot welding is also partly due to the large self-discharge of the battery itself.
Battery explosion generally has the following situations:
1. Overcharge explosion
The protection circuit is out of control or the detection cabinet is out of control to make the charging voltage greater than 5V, causing the electrolyte to decompose, a violent reaction occurs inside the battery, the internal pressure of the battery rises rapidly, and the battery explodes.
2. Overcurrent explosion
The protection circuit is out of control or the detection cabinet is out of control, so that the charging current is too large and the lithium ions are too late to be inserted. Lithium metal is formed on the surface of the pole piece, penetrates the diaphragm, and the positive and negative electrodes are directly short-circuited and cause explosion (rarely).
3. Explosion when ultrasonic welding plastic shell
When ultrasonic welding the plastic shell, the ultrasonic energy is transferred to the battery core due to the equipment. The ultrasonic energy is so large that the internal diaphragm of the battery melts, and the positive and negative electrodes are directly short-circuited, causing an explosion.
4. Explosion during spot welding
Excessive current during spot welding caused serious internal short-circuit and explosion. In addition, during spot welding, the positive electrode connecting piece was directly connected to the negative electrode, causing the positive and negative electrodes to directly short-circuit and explode.
5. Over discharge explosion
Battery over-discharge or over-current discharge (above 3C) easily dissolves and deposits the negative electrode copper foil on the separator, causing the positive and negative electrodes to be directly short-circuited to cause explosion (rarely).
6. Explode when vibration falls
The internal pole piece of the battery is dislocated when the battery is violently vibrated or dropped, and it is directly short-circuited and exploded (rarely).
6. Low battery 3.6V platform
1. Inaccurate sampling of the detection cabinet or unstable detection cabinet caused the test platform to be low.
2. Low ambient temperature causes low platform (discharge platform is greatly affected by ambient temperature)
Seven, caused by improper processing
(1) Move the positive electrode connection piece of spot welding forcefully to cause poor contact of the positive electrode of the battery cell, which makes the internal resistance of the battery core large.
(2) The spot welding connection piece is not firmly welded, and the contact resistance is large, which makes the battery internal resistance large.
In short, to choose lithium battery products, you must choose high-quality, high-quality lithium battery products produced by professional lithium battery manufacturers to effectively avoid problems. Qianguo Electronics, a professional lithium battery product and service provider.