The battery bad projects and causes

1. Capacity is low

Reason:

attached to quantity less than normal; pole piece attached quantity on both sides quite different; c pole piece fracture;

d. less electrolyte; e electrolyte conductivity; f. piece of positive and negative with not equipped;

g membrane porosity; h. adhesive aging → attached material off; i core ultra-thick (not dried or electrolyte does not permeate)

j sub-capacity is not fully charged; k. positive and negative material than the small capacity.

2 high internal resistance

Reason:

a. negative piece extremely ear Weld; to b. cathode piece with very ears Weld; a c. cathode ear cap Weld;

d. negative ear shell Weld; e. rivets platen contact resistance; f. cathode not add conductive agent;

g. lithium salt electrolyte; h. batteries had a short circuit; i. separator paper porosity.

3 low voltage

Reason:

a side reaction (decomposition of the electrolyte; positive impurities; water); unformed (SEI film is not formed security);

c. customer PCB leakage (the batteries sent back to the customer after processing); d. customers did not seek a spot welding (batteries) customer processing;

e. burr; f. slightly short circuit; g. negative a dendrite.

4 extra-thick

Produce extra-thick for the following reasons:

a. welds leak; decomposition of the electrolyte; c. drying moisture;

d cap sealing difference; e shell wall thick; f shell thick;

g core is too thick (attached material too; pole piece Uncompacted; the diaphragm too thick).

5 causes the following

a. unformed (SEI film is incomplete, dense); baking temperature is too high → binder aging → stripper; c. negative than low capacity;

d. attached material positive and negative attached less material; e cap leak, weld leak; f. decomposition of the electrolyte, the conductivity decreases.

6 explosion

a sub-capacity cabinet failure (excess charge); b diaphragm closed effect; c. internal short circuit

7 short-circuit

a. material dust; b shell loaded fashion break; c. feet scraping (small separator paper is too small or not good pad);

d. winding arrhythmia; e did not wrap; f. diaphragm with holes; g. glitch

8 breaker

a) the extremely ear and rivets is not welded good or effective solder joint area;

b) the connection piece fracture (connecting piece is too short or the pole piece spot welding welding too bottom)

1, the basic working principle

1) Positive reaction: of LiCoO2 ===== of Li1 xCoO2 + x Li + + xe-

2), a negative electrode reaction: 6C + x Li + + xe-===== LixC6

3) batteries reaction: of LiCoO2 + 6C ====== Li1-xCoO2 + LixC6

4), the electromotive force of the battery:

(1) Definition: In the case of no current, the battery positive and negative electrode potential difference across.

(2), the impact of factors: the decision by the electrode material, without any other supporting material.

2, the voltage characteristic

1), open circuit voltage: direct measurement of the voltage across the positive and negative voltmeter.

        E = V - I R

2) The operating voltage range: 2.75 ~ 4.2 volt.

3) Rated voltage: 3.6 volt.

4), the average working voltage: 3.72 volt.

5), the basic factors affect the voltage characteristic

(1), the electrode material; (2), electrode formulation; (3), the cell design;

4 Current:

1), the polarization of the electrode: the current through the battery electrode, resulting in the electrode potential deviates from the equilibrium state.

ohmic polarization: the resistance of the battery materials.

electrochemical polarization: The pros and cons of the ease of electronic, resulting in the electrode potential deviation from the equilibrium state.

c, concentration polarization: slow ion mobility, resulting in the electrode potential deviation from the equilibrium state.

2) the relationship between the polarization current: ie <ir <ic
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2), the determination of the operating current: "ic; 2-3 mA/cm2;

3), the factors that affect the operating current

(1), electrode formulation, a conductive material properties, the dosage, the binder amount.

(2), the area of ??the pole pieces;

(3), a pole piece compaction density;

(4), the thickness of the passivation film;