High-power energy storage device shelving method

Abstract

The invention discloses a high-power energy storage device shelving method in the technical field of high-power energy storage devices, and the method comprises the following steps: 1, shelving a certain number of energy storage devices in an environment of 40-45 DEG C for 6-8 days, measuring the voltage Vi of the energy storage devices after shelving, and performing interval RV, the optimal interval RVn representing the average level of the batch of energy storage devices; 2, placing the energy storage device in the optimal interval RVn at an alternating temperature: placing the energy storage device in an environment of 40-45 DEG C for 3-4 days, and placing the energy storage device in an environment of 0-5 DEG C for 3-4 days; the voltage Vi (1) of the energy storage device is measured after shelving is finished, and the optimal interval # imgabs0 # represents the average level of the energy storage device after one-time alternating temperature shelving; and 3, placing the energy storage device in the optimal interval # imgabs 1 # at an alternating temperature: placing the energy storage device in an environment of 0-5 DEG C for 2.5-3.5 days, and placing the energy storage device in an environment of 40-45 DEG C for 0.5-1.5 days. According to the shelving method, the stability performance of the energy storage device can be remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of high-power energy storage devices, and in particular relates to a method for placing a high-power energy storage device. Background Art

[0002] High-power energy storage devices, such as lithium-ion batteries and supercapacitors, play a key role in electric vehicles, aerospace, smart grids, and portable electronic devices. During storage, these devices may undergo a series of adverse physical and chemical changes, resulting in performance degradation, especially when not properly maintained. These changes include, but are not limited to, self-discharge, electrolyte decomposition, loss of active materials, and structural degradation.

[0003] Self-discharge is one of the main reasons for performance loss during storage device storage. It refers to the spontaneous reduction of charge caused by the current inside the device in an open circuit state. The self-discharge rate is affected by many factors such as temperature, electrode materials, electrolyte composition and device design. High temperature accelerates the reaction between electrode materials and electrolytes, thereby increasing the self-discharge rate. In addition, the self-discharge rate varies greatly between different energy storage devices, and this difference will be further amplified during the storage process, resulting in increased performance dispersion of the same batch of devices.

[0004] Therefore, developing an effective shelving method to slow down the performance degradation of energy storage devices during the shelving period and improve their long-term stability and consistency is of great significance for extending the service life of the devices and reducing maintenance costs. Summary of the invention

[0005] The present invention is intended to provide a high-power energy storage device shelving method to suppress the internal chemical reaction rate of the energy storage device, thereby extending the shelving time and improving the stability of the energy storage device.

[0006] A high-power energy storage device shelving method in this scheme comprises the following steps:

[0007] Step 1: Place a certain number of energy storage devices in a 40℃~45℃ environment for 6~8 days, and measure their voltage V after the placement. i , use formula (1) to divide the energy storage device into interval RV, the optimal interval RV n Represents the average level of this batch of energy storage devices;

[0008]

[0009] Among them, max{V i}、min{V i} respectively represent the voltage V of the energy storage device after being left at 40℃~45℃ i The maximum and minimum values ​​of

[0010] Step 2: Set the optimal interval RV n The energy storage device is placed under alternating temperature: 3 to 4 days at 40℃ to 45℃, and 3 to 4 days at 0℃ to 5℃; after the placement, the voltage is measured. Interval RV (1) , the optimal interval Represents the average level of the energy storage device after an alternating temperature shelving;

[0011] Step 3: Set the optimal interval The energy storage device is placed under alternating temperature: 2.5 to 3.5 days at 0℃ to 5℃, and 0.5 to 1.5 days at 40℃ to 45℃.

[0012] This solution has the following beneficial effects:

[0013] 1. Improve the stability of energy storage devices: By placing the energy storage devices in an environment of 40℃~45℃, devices with fast self-discharge can be quickly eliminated. This stage can effectively reduce the mixing of devices that may experience rapid performance degradation in subsequent use into the overall batch, thereby improving the stability foundation of the entire batch of energy storage devices. Then place them at alternating temperatures, especially first at a higher temperature to further accelerate the performance degradation of devices with large self-discharge, making them easier to identify and eliminate; then give the energy storage devices a certain "rest" time at low temperatures to reduce the occurrence of adverse chemical reactions. This method can gradually screen out energy storage devices with more stable performance and further improve the overall stability level. Finally, by cyclically placing them between 0℃~5℃ and 40℃~45℃, the difference in chemical reaction rates at different temperatures can be used to suppress the situation where the chemical reaction rate inside the energy storage device is too strong. In the high temperature stage, although the chemical reaction may accelerate, it can also make potential unstable factors appear more quickly, which is convenient for subsequent screening and adjustment; in the low temperature stage, the chemical reaction slows down, which helps to stabilize the performance of the energy storage device and reduce the risk of accelerated attenuation rate. This cyclic shelving method can continuously optimize and stabilize the energy storage device, greatly improving its long-term stability.

[0014] 2. Enhance the consistency of energy storage devices: By using formula (1) to compartmentalize energy storage devices that have been shelved at different stages, we can clearly distinguish groups of devices with different performances. By continuously screening out energy storage devices in the optimal interval, the devices that are finally left are closer in performance, reducing the performance differences between devices in the same batch and enhancing consistency.

[0015] 3. Extend service life and reduce maintenance costs: Through the above series of shelving methods, the chemical reaction rate inside the energy storage device is effectively suppressed. The adverse processes such as self-discharge, electrolyte decomposition, loss of active substances and structural degradation are slowed down, thereby extending the service life of the energy storage device. For high-power energy storage devices, their cost is relatively high. Extending the service life means that the overall cost of use and maintenance costs can be reduced. Through screening and optimization, the risks that may be brought about by devices with faster performance degradation during use, such as sudden failure, sudden capacity reduction and other problems, are reduced. This not only improves the reliability of the energy storage system, but also reduces the cost of frequent maintenance and replacement due to performance degradation.

[0016] Furthermore, the voltage of the energy storage device was monitored at the end of every 10 cycles. Interval RV (m×10) (m=1,2,3,......), optimal interval This means that the voltage discreteness of the energy storage device is the smallest after every 10 cycles of alternating temperature. That is, the voltage range is small. (m=1, 2, 3, ...) are infinitely close, indicating that the performance of the energy storage device during the shelf period is similar or the decay rate is consistent. By monitoring the voltage change of the energy storage device during the shelf period, the alternating temperature and shelf time can be adjusted in time to adapt to different batches and models of energy storage devices. This helps to meet the requirements for the performance stability of energy storage devices in different application scenarios.

[0017] Furthermore, the high-power energy storage device is a lithium-ion battery or a battery-type capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic flow chart of a method for placing a high-power energy storage device. DETAILED DESCRIPTION

[0019] The following is further described in detail through specific implementation methods:

[0020] Embodiment 1: A method for placing a high-power energy storage device comprises the following steps:

[0021] 1. The same batch (or a certain number) of energy storage devices are placed in a 40℃~45℃ environment for 7 days, and their voltage V is measured after the placement. i , use formula (1) to divide the energy storage device into interval RV, the optimal interval RV n It represents the average level of the same batch (or a certain number) of energy storage devices. Shelving at 40℃~45℃ is to eliminate energy storage devices with fast self-discharge as much as possible;

[0022]

[0023] Where max{V i}、min{V i} The voltage V of the energy storage device after being placed at 40℃~45℃ i The maximum and minimum values ​​of .

[0024] 2. Set the optimal interval RV n The energy storage device is placed under alternating temperature: 3.5 days at 40℃~45℃, and 3.5 days at 0℃~5℃. After the placement, the voltage is measured. Interval RV (1) , the optimal interval Represents the average level of energy storage devices after one alternating temperature standby. This step is to further eliminate energy storage devices with large self-discharge under alternating temperature standby;

[0025] 3. The optimal interval The energy storage device is placed under alternating temperature: 3 days at 0℃~5℃, and 1 day at 40℃~45℃. The alternating temperature setting is mainly used to suppress the excessive chemical reaction rate inside the energy storage device, which accelerates its decay rate.

[0026] 4. Monitor the voltage of the energy storage device at the end of every 10 cycles Interval RV (m×10) (m=1,2,3,......), optimal interval This means that after every 10 cycles of alternating temperature storage, the voltage discreteness of the energy storage device is minimal (i.e., the voltage extreme difference is small). By monitoring the voltage, different alternating temperatures and their respective storage times can be adjusted in a timely manner.

[0027] 5. Each optimal interval Infinitely close, indicating that the performance during the storage period is similar or the decay rate is consistent during the shelving period.

[0028] The comparative experiment is as follows:

[0029] Comparison 1

[0030] A batch of energy storage devices (1000 samples, initial voltage 3.7V) were divided into two parts, one part was shelved using the patented method (Example 1, the same below), and the other part was shelved using the conventional method (room temperature change, 10°C ~ 35°C). After the initial shelving for 6 days, the voltage interval RV was measured. The results are shown in Table 1. The initial high-temperature shelving of the patented method has a screening effect, that is, the optimal intervals RV2 and RV3, while the voltage of the conventional method is relatively dispersed after 6 days of shelving, mostly concentrated between RV1 and RV4.

[0031] Table 1

[0032]

[0033] The optimal intervals RV2 and RV3 obtained by the patented method were shelved under alternating temperatures: 3 days at 40℃~45℃, and 4 days at 0℃~5℃. The intervals RV1~RV4 obtained by the conventional method were still shelved in the conventional manner for 7 days. The results are shown in Table 2. After the alternating temperature shelving of the patented method, the number of samples in the intervals RV2 (170→166) and RV3 (201→195) decreased less, while the intervals RV1~RV4 of the conventional method all decreased to varying degrees, and the total number decreased more than that of the patented method.

[0034] Table 2

[0035]

[0036] Patented method and The alternating temperature cycle was performed: 3.5 days at 0℃~5℃, and 0.5 days at 40℃~45℃; the conventional method was used to obtain The conventional method is still used for the same shelf time as the patent method. Table 3 is a comparison of the results of 50 times (200 days) of alternating temperature cycle shelf and the conventional method shelf. The patent method reduces the number of samples less than the conventional method.

[0037] Table 3

[0038]

[0039]

[0040] Comparison 2

[0041] The modules (1# to 44# are all 5 parallel and 14 series, with an initial voltage of 51.6V) were placed under alternating temperature: 3.5 days at 0℃ to 5℃, and 0.5 days at 40℃ to 45℃. Compared with the conventional method, the results are shown in Table 4. It can be seen that the voltage of the modules placed under alternating temperature is higher, indicating that the patented method is also beneficial to the placement of the modules.

[0042] Table 4

[0043] Module number 1# 2# Patented method to set the voltage / V 51.538 51.533 Module number 3# 4# Conventional method shelving voltage / V 51.197 51.182

[0044] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for placing a high-power energy storage device, characterized in that: The following steps are involved: Step 1: Place a certain number of energy storage devices in a 40℃~45℃ environment for 6~8 days, and measure their voltage V after the placement. i , use formula (1) to divide the energy storage device into interval RV, the optimal interval RV n Represents the average level of this batch of energy storage devices; Among them, max{V i }、min{V i } respectively represent the voltage V of the energy storage device after being left at 40℃~45℃ i The maximum and minimum values ​​of Step 2: Set the optimal interval RV n The energy storage device is placed under alternating temperature: 3 to 4 days at 40℃ to 45℃, and 3 to 4 days at 0℃ to 5℃; after the placement, the voltage V is measured. i (1) , perform interval RV (1) , the optimal interval Represents the average level of the energy storage device after an alternating temperature shelving; Step 3: Set the optimal interval The energy storage device is placed under alternating temperature: 2.5 to 3.5 days at 0℃ to 5℃, and 0.5 to 1.5 days at 40℃ to 45℃.

2. A method for placing a high-power energy storage device according to claim 1, characterized in that: The voltage of the energy storage device is monitored at the end of every 10 cycles. Interval RV (m×10) (m=1,2,3,......), optimal interval This means that the voltage discreteness of the energy storage device is minimal after every 10 cycles of alternating temperature. That is, the voltage extreme difference is small.

3. A method for placing a high-power energy storage device according to claim 1 or 2, characterized in that: The high-power energy storage device is a lithium-ion battery or a battery-type capacitor.

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