Digital battery

Lithium-ion batteries is a new type of battery, it does not contain lithium metal in the charge-discharge process, only the lithium-ion in the positive and negative exchanges between the campaigns, the electrode and electrolyte not participating in the reaction. Lithium-ion batteries for energy densities can reach 300Wh / L, the density of the payload can reach 125Wh / L.

 

1, Principles of batteries

Lithium-Ion batteries, with charges reaction mechanism of the discharge pipe, the lithium ions between positive and negative electrodes embedded in a prolapse, shuttle to and from the internal VGP-BPS10 battery without the presence of lithium metal, lithium-ion batteries more security and stability. The reaction scheme and the formula of basic reaction is:

 

2, construction of piers

The positive is LiCoO2 batteries and more conductive adhesives, coated aluminum foil to form the positive plate, the negative electrode is a conductive layer of graphite as well as agents and adhesive coatings based on copper particles Graphite is now more advanced layers were negative using nano-carbon.

 

The mechanism of above reaction, the positive use of LiCoO2, LiNiO2, LiMn2O2 which this is a structure of LiCoO2 layer forms very stable crystal, but when away from LiCoO2 XLI, its structure may change, but if change depends on the X size. Through research has found that when X> 0.5, where the structure of Li1-XCoO2 expressed in extremely unstable and collapse occurs paralysis crystal, its outdoor performances of the end for the batteries overwhelming. Therefore, as part of VGP-BPS9 batteries must be controlled by limiting the charging voltage Li1-XCoO2 the value of X, the general tariff, the voltage does not exceed 4.2 V when X is less than 0.5, XCoO2-li1 then the crystal is always stable. C6 has its negative characteristics of its own, when for the first time after the LiCoO2 cathode of Li is sufficient to negative C6, when the discharge Li returned to the LiCoO2 cathode, but must be followed in a part of Li C6 remained negative, the heart of ensuring that the next charge and discharge embedding normal Li batteries otherwise overwhelming very short to ensure that there are part of the Li remained negative C6 The general threshold voltage by limiting the discharge to achieve. Therefore, the safety of lithium rechargeable batteries, the maximum voltage ≤ 4 .2 V, discharge lower limit voltage ≥ 2.5V.

 

3, the battery safety

Batteries for safety and design, materials and control of production processes in the production process is closely related to other factors. In IBM ThinkPad R51 battery charging and discharge process, the positive electrode potential anode materials are in dynamic change, with the voltage higher load, the cathode material (LixCoO2) the upside potential, the anode material for the insertion of lithium (LixC6) potential first down, then the potential emergence of a long platform, when the charging voltage is too high (> 4.2V) or because the negative electrode material of the surface density over the surface density of cathode material (C / A ratio) is low, excess lithium anode material, the cathode potential down rapidly and so the precipitation of lithium metal (in Under normal circumstances, it will not be the precipitation of lithium), it will be the performance of batteries and safety is a major threat. Potential changes see below:

 

In the matter has been defined circumstances, C / A too large, it will appear above the results. Instead, C / A is too small, the capacity is low platform, low cycle characteristics of the poor. Thus, in the production and transformation of the way to ensure the design of a good C / A ratio has become a key production and processing. Therefore, production must be controlled on the following aspects:

 

1. Materials handling anode

1) The large and ultra-fine powder with a particle size necessary for a complete separation, avoiding overheating local electrochemical reaction resulting from a negative reaction, to improve Dell Inspiron 1150 battery safety.

2) increasing the surface porosity, which can increase capacity by more than 10%, while C / A rate unchanged, security increased dramatically. Treatment led to the surface of anode materials for better compatibility with the electrolyte, and promote the formation of SEI film and stabilization.

2. Pulping process control

A) Process of pulping using methods and advanced technology of special chemical reagents, so that positive and negative slurry surface tension between the groups minimized. Improve the compatibility between the different groups to prevent the material in the mixing process “Reunion” phenomenon.

2) The time-based coating materials and spray the gap should be controlled to 0.2 mm below the surface of such a plate covered with smooth without particles, dents, scratches and other defects.

3) The suspension should be stored for more than 6 hours, the viscosity of the slurry remained stable in the Territories, slurry polymerization in a group phenomenon. Grout to ensure uniform distribution of positive and negative electrodes on the uniformity of the substrate, thereby improving the consistency of batteries, security.

 

3. The most advanced equipment for manufacturing chips

1) a pole piece can ensure stability and consistency of quality has greatly improved the uniformity of the F2024B battery pole piece, reducing the likelihood of the emergence of hazardous batteries.

2) monolithic plate coating machine exceeds the value of error density must be less than ± 2%, length of the plate and the size of the gap error must be less than 2 mm.

3) The rolls of the press roller cone and radial runout shall not be greater than 4μm, to ensure consistency of thick plates. The equipment must be equipped with a comprehensive collection of dust to prevent dust particles caused by the internal micro-batteries short-circuit, thus ensuring self-discharge performance of batteries.

4) cutting machine must be used as a knife-type cutting rolls cutting a continuous device, and cut the film is not quite there Yebian, burrs and other defects. The same device should be equipped with a comprehensive collection of dust, ensuring self-discharge performance of batteries.

 

4. Advanced Sealing Technology

At home and abroad square lithium-ion VGP-BPS8A batteries are sealed laser (laser) welding sealing technology, which prohibits the use of YAG (yttrium aluminum garnet) laser resonant cavity exposed to a source of bright light (usually the lamp nitrogen) to issue a bunch of inspired one frequency of light (λ = 1.06mm) was concentrated in an infinite number of refracted through the resonator, then concentrate on the Guidance cell alignment between the cylinder and the cover so that after the merger of affinity for one to reach the cover plate and the tube The objective of the merger sealing body. In order to achieve sealing welding, must contain the following elements:

1) It must be great energy, high frequency, focused performance monitoring and precision of the laser welding machine.

2) It must be applied to high precision laser welding of the shell and battery cover.

3) It must have a high degree of purity nitrogen uniform protection, especially aluminum batteries require high purity nitrogen, or aluminum surface will be difficult to produce molten Al2O3 (melting point 2400 ℃ ).

4) batteries and expansion control reasons

Lithium-ion batteries in the manufacture and use, there is often swelling of the phenomenon through the analysis and research are essentially two reasons:

Drowned in a lithium-ion led to changes in the thickness

Lithium rechargeable ion batteries where the anode from the cathode board prolapse, causing negative electrode layer spacing increases, but the swelling is, in general, the thicker apple iBook G4 14 inch battery, plus the amount of expansion.

 

2. Caused by the expansion process of poor control

During the manufacturing process, such as dispersion slurry, C / A than in discrete, temperature control directly affects the expansion of cells able batteries. Including water, because the rechargeable lithium formation of compounds with high carbon activity is very sensitive to water is a tug of chemical reactions. Gases produced by the reaction caused by the cell pressure is increased, an increase in the swelling behavior of batteries. Therefore, in production, in addition to dealing with the dehumidifier plate strict fluid injection in the process of dehumidification equipment should be used to ensure the dryness of the HR2% air, the dew point ( in the atmosphere of moist air due to temperature drop, so that the content of saturated water vapor began to condense when the temperature) is lower than -40 ℃. In very dry conditions, and taking fluids injected under vacuum, greatly reducing the chances of plates and electrolyte absorption.

5, aluminum and steel batteries comparison of the security

Aluminum over steel with high security benefits, the following is different from the pressure of the experience:

 

Note: The pressure is the pressure of batteries within the pressure (unit: kg), the data tables of a core electrical thickness (unit: mm) of steel can be considered to result internal pressure is very slow, while the internal pressure aluminum reaction was very acute. Therefore, from the thickness can be judged on the basis of battery internal pressure while the pressure of steel piles are often induced by the implicit hidden dangers. A steel model 063,448 batteries.