Composite battery

Abstract

The invention discloses a composite battery. The composite battery comprises at least one lead-acid battery pack and at least one lithium ion battery pack connected in parallel with the lead-acid battery pack, wherein single lead-acid batteries in the lead-acid battery pack have electrolytes with the density of 1.29-1.33g / ml, and / or, the positive poles / negative poles of single lithium ion batteries in the lithium ion battery pack contain an active substance, the active substance at the positive poles of the single lithium ion batteries is at least one of lithium iron phosphate, lithium manganate, lithium cobalt oxide, a ternary material and the like, and the active substance at the negative poles is at least one of graphite, mesocarbon microbeads, lithium titanate and the like; and the proportion of the total open-circuit voltage of branch circuits of the lead-acid battery pack and that of branch circuits of the lithium ion battery pack is 0.99-1.01:1. By adopting the composite battery provided by the invention, the total open-circuit voltage of the lithium ion battery pack is matched with that of the lead-acid battery pack, so that the lead-acid batteries are prevented from damage, and the service life of the lead-acid batteries is prolonged; and meanwhile, the composite battery has the advantages of simple structure, easiness in implementation and low cost.

Description

technical field [0001] The invention relates to a composite battery. Background technique [0002] As we all know, lead-acid batteries and lithium-ion batteries are secondary batteries belonging to different chemical systems, and each has its own unique characteristics. A simple comparison of lead-acid batteries and lithium-ion batteries is shown in Table 1: [0003] Table 1 [0004] [0005] Lead-acid battery has the advantages of stable voltage, safety and reliability, low price, wide application range, abundant raw materials and high recycling rate. It is the battery with the largest output and widest application among all kinds of batteries in the world. , backup power sources such as banks, solar and wind energy storage, automobiles, motorcycles and electric vehicles. However, lead-acid batteries have also exposed many limitations in the application process: [0006] 1. The weight specific energy is too low, only 30WH / KG; [0007] 2. The cycle life is short. As ...

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Problems solved by technology

However, lead-acid batteries have also exposed many limitations in the application process:

[0006] 1. The weight specific energy is too low, only 30WH / KG;

[0007] 2. The cycle life is short. As a battery for electric vehicles, it needs to be replaced after about one year of use;

[0008] 3. When under-charging, it is easy to cause sulfation of the plate, which seriously shortens the battery life; such as lead-acid batteries for electric vehicles, wind energy and solar energy, because the battery is often not fully charged in time, the battery is partially charged Recycled use under the state, which will cause sulfation of the plate, resulting in accelerated capacity attenuation and severe shortening of life;

[0009] 4. Not suitable for high current discharge; such as figure 1 It shows that when discharging at different rates, the battery capacity is equivalent to the ratio of 1C1 rate discharging battery capacity

When the electrical appliances used work at a higher power, the actual working time of the battery is significantly shortened, resulting in the failure to reach the nominal capacity;

[0010] 5. The low-temperature characteristics are poor, and it is difficult to work normally when it is lower than minus 20°C

[0025] 3. The above literature does not involve how to choose a suitable and different type of secondary battery system, a composite energy system that is more reasonable by adjusting its structure and internal composition, and does not use battery management components for charge / discharge control

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