The structural design of lithium-ion battery packs is an important part of the entire battery pack system design, and it is a time-consuming part of the entire design process. Let's take a look at the factors that affect the structural design of lithium-ion battery packs.

The basic structure of lithium-ion battery packs

Important materials: anode, cathode, electrolyte, separator

Structure: round, square lamination, wind

Form: Polymer (flexible packaging), liquid ion (box hat)

The influence of different factors on the structural design of lithium-ion battery packs

Trend of discharge characteristic curve

The trend of the discharge characteristic curve is closely related to the slope rate of the battery cell discharge curve. The basic discharge trend varies for different types of battery cells.

The power delivered by a battery with a slope discharge curve gradually decreases throughout the entire discharge cycle. This may cause problems for high-power applications at the end of the discharge phase. For low-power applications that require stable power supply voltage, if the slope is too steep, a voltage regulator may need to be installed. This is usually not suitable for high-power applications, as the loss of the voltage regulator consumes too much power from the battery.

Ambient temperature

The discharge characteristics of batteries are significantly influenced by environmental temperature. If the usage environment of lithium-ion battery packs is below 0 °C, the electrolyte itself may freeze in some batteries containing electrolyte; Even if the organic electrolyte does not freeze and the performance of the battery deteriorates significantly, the impact of low temperature on the battery should be considered. If power lithium-ion batteries are used in high temperature environments, the electrode active material is prone to react with the electrolyte at high temperatures, which may result in capacity loss and potential risks.

Within the temperature range that the battery can withstand, the performance of the battery usually increases with the increase of temperature, such as an increase in capacity and a decrease in internal resistance. Each type of battery cell has a suitable working temperature, and the ideal scenario is to give the battery this suitable working temperature. High or low temperatures can affect the cycle life.

Pulse performance

The ability to deliver high current pulses is a requirement for many batteries. The current carrying capacity of a battery depends on the surface area of the electrodes. But the current limit is determined by the rate of chemical reactions occurring within the battery. When there are requirements for the power usage range of batteries, understanding the pulse capability of the battery cells can help design more suitable lithium-ion battery pack cells.

After determining the scope of use, environment, and other factors that affect the structural design of lithium-ion battery packs, and after designing lithium-ion battery packs, it is necessary to test their performance, stability, and practicality.