A lithium-ion battery matching method based on battery characteristic vector

Abstract

The present invention relates to the technical field of lithium-ion battery grouping, and discloses a lithium-ion battery grouping method based on battery characteristic vectors, comprising the following steps: Step 1: Under normal temperature, the capacity, voltage and internal resistance of the lithium battery are measured, and then simultaneously measured under normal temperature. The present invention first tests and groups the capacity, voltage and internal resistance of the lithium battery under normal temperature, and then groups them again according to the parameters under different power discharge conditions, then puts the battery in an extreme environment of high temperature or low temperature, and then performs a normal power or high power discharge test, and again obtains the performance parameters under high temperature and low temperature and groups them again, and finally tests the performance of the lithium battery under a vibration environment, and finally selects lithium batteries with the same performance parameters under various environments to obtain a lithium battery group, so that the parameters of the lithium battery working in different environments remain unchanged, thereby ensuring the overall performance and safety of the lithium battery group.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion battery assembly, in particular to a lithium ion battery assembly method based on battery characteristic vectors. Background Art

[0002] At present, with the development of society, the application of lithium-ion batteries is becoming more and more extensive. In practical applications, in order to adapt to the requirements of the load, dozens or even hundreds of single cells are often required to be assembled together in series or in parallel to meet the needs of high voltage and high capacity. Theoretically, the internal resistance, capacity and other parameters of these batteries should be as consistent as possible so that the power released by the battery can be maximized. However, due to the influence of production conditions, manufacturing environment, material properties and equipment, there are differences in the same batch. In practical applications, single cells with relatively good consistency must be selected through grouping strategies for grouping and assembly, so that the overall performance of the battery pack can reach a satisfactory level.

[0003] The existing technology of grouping is to file and group according to the battery's capacity, voltage, internal resistance and other characteristics, so that the performance parameters of lithium batteries are as consistent as possible. However, in actual use, lithium batteries are more affected by temperature, and it is necessary to group their parameters under different temperature conditions. At the same time, it is also necessary to test the performance of lithium batteries under the influence of vibration, otherwise there will still be differences in parameters between the batteries, affecting the overall performance. Therefore, we propose a lithium-ion battery grouping method based on battery feature vectors. Summary of the invention

[0004] The object of the present invention is to provide a lithium-ion battery grouping method based on battery characteristic vectors, by first testing and grouping the capacity, voltage and internal resistance of lithium batteries under normal temperature, and then grouping them again according to the parameters under different power discharge conditions, then subjecting the batteries to extreme high or low temperature environments, and then subjecting the batteries to normal power or high power discharge tests, and again obtaining the performance parameters at high and low temperatures and grouping them again, and finally subjecting the lithium batteries to performance tests under a vibration environment, and finally selecting lithium batteries with the same performance parameters under various environments to group and obtain a lithium battery group, so that the parameters of the lithium batteries working in different environments remain unchanged, thereby ensuring the overall performance and safety of the lithium battery group, and solving the problems raised in the background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a lithium-ion battery assembly method based on battery characteristic vectors, comprising the following steps:

[0006] Step 1: Under normal temperature, measure the capacity, voltage and internal resistance of the lithium battery. Then measure the voltage and internal resistance of the lithium battery at normal power discharge and high power discharge under normal temperature. Also measure the temperature of the lithium battery during discharge. Then select the lithium batteries with the same parameters to prepare for the next step of grouping.

[0007] Step 2: Select lithium batteries in the same group as above, heat all lithium batteries to a certain temperature, measure the voltage and internal resistance of the lithium batteries again, and then continue to discharge the lithium batteries at normal power and high power in the heated environment, and measure the voltage and internal resistance during the discharge process, and screen out lithium batteries with the same parameters again;

[0008] Step 3: Continue to select lithium batteries in the same group as above, cool all lithium batteries to a low temperature environment, measure the voltage and internal resistance of the lithium batteries again, and then continue to discharge the lithium batteries at normal power and high power in a low temperature environment, and measure the voltage and internal resistance during the discharge process, and screen out lithium batteries with the same parameters again;

[0009] Step 4: Select lithium batteries in the same group as above, place all lithium batteries on the surface of the vibration table, and then place the lithium batteries in a high vibration environment. First, measure the voltage and internal resistance of the lithium batteries. Then, measure the voltage and internal resistance of the lithium batteries in the vibration environment, normal discharge and high-power discharge, and measure the battery temperature at the same time, and finally obtain lithium batteries with the same parameters.

[0010] Step 5: Finally, assemble the lithium batteries in the same group. After assembly, test their stability and safety again. Qualified lithium battery packs can be used.

[0011] As a preferred embodiment of the present invention, in the steps 1 to 4, a programmable DC electronic load can be used to load the battery, and the voltage and internal resistance parameters in the process can be measured simultaneously.

[0012] As a preferred embodiment of the present invention, the battery temperature in step 1 and step 4 can be measured by a patch temperature sensor, and a plurality of temperature sensors need to be attached to each lithium battery.

[0013] As a preferred embodiment of the present invention, the test temperature of the lithium battery in step 2 is 50°C to 60°C, and the test temperature of the lithium battery in step 3 is -25°C to -15°C.

[0014] As a preferred embodiment of the present invention, the lithium battery in step 2 and the lithium battery in step 3 are both placed on a copper soaking plate, and then heated by an electric heater or cooled by an evaporator.

[0015] As a preferred embodiment of the present invention, the lithium battery in step 4 needs to be mounted on the surface of the vibration table using special fasteners to prevent the lithium battery from being shaken off.

[0016] As a preferred embodiment of the present invention, the lithium batteries in step five are assembled in series and connected by power lines.

[0017] As a preferred embodiment of the present invention, the lithium battery pack in step five is tested for performance and safety by means of a programmable DC electronic load meter and a temperature sensor.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention first tests and groups the capacity, voltage and internal resistance of lithium batteries under normal temperature, and then groups them again according to the parameters under different power discharge conditions. The batteries are then placed in extreme high or low temperature environments, and then subjected to normal power or high power discharge tests. The performance parameters at high and low temperatures are obtained again and grouped again. Finally, the performance of the lithium batteries is tested in a vibration environment, and finally lithium batteries with the same performance parameters under various environments are selected for grouping to obtain a lithium battery pack, so that the parameters of the lithium batteries working in different environments remain unchanged, thereby ensuring the overall performance and safety of the lithium battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0021] Figure 1 The present invention is a flow chart of a lithium-ion battery grouping method based on battery characteristic vectors. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0023] See also Figure 1 The present invention provides a technical solution: a lithium-ion battery assembly method based on battery characteristic vectors, comprising the following steps:

[0024] Step 1: Under normal temperature, measure the capacity, voltage and internal resistance of the lithium battery. Then measure the voltage and internal resistance of the lithium battery at normal power discharge and high power discharge under normal temperature. Also measure the temperature of the lithium battery during discharge. Then select the lithium batteries with the same parameters to prepare for the next step of grouping.

[0025] Step 2: Select lithium batteries in the same group as above, heat all lithium batteries to a certain temperature, measure the voltage and internal resistance of the lithium batteries again, and then continue to discharge the lithium batteries at normal power and high power in the heated environment, and measure the voltage and internal resistance during the discharge process, and screen out lithium batteries with the same parameters again;

[0026] Step 3: Continue to select lithium batteries in the same group as above, cool all lithium batteries to a low temperature environment, measure the voltage and internal resistance of the lithium batteries again, and then continue to discharge the lithium batteries at normal power and high power in a low temperature environment, and measure the voltage and internal resistance during the discharge process, and screen out lithium batteries with the same parameters again;

[0027] Step 4: Select lithium batteries in the same group as above, place all lithium batteries on the surface of the vibration table, and then place the lithium batteries in a high vibration environment. First, measure the voltage and internal resistance of the lithium batteries. Then, measure the voltage and internal resistance of the lithium batteries in the vibration environment, normal discharge and high-power discharge, and measure the battery temperature at the same time, and finally obtain lithium batteries with the same parameters.

[0028] Step 5: Finally, assemble the lithium batteries in the same group. After assembly, test their stability and safety again. Qualified lithium battery packs can be used.

[0029] Furthermore, in the steps 1 to 4, a programmable DC electronic load can be used to load the battery, and the voltage and internal resistance parameters in the process can be measured simultaneously.

[0030] Furthermore, the battery temperature in step 1 and step 4 can be measured by a patch temperature sensor, and a plurality of temperature sensors need to be attached to each lithium battery.

[0031] Furthermore, the test temperature of the lithium battery in step 2 is 50°C to 60°C, and the test temperature of the lithium battery in step 3 is -25°C to -15°C.

[0032] Furthermore, the lithium battery in step 2 and the lithium battery in step 3 are both placed on a copper soaking plate, and then heated by an electric heater or cooled by an evaporator.

[0033] Furthermore, the lithium battery in step 4 needs to be mounted on the surface of the vibration table using special fasteners to prevent the lithium battery from being shaken off.

[0034] Furthermore, the lithium batteries in step five are assembled in series and connected via power lines.

[0035] Furthermore, the lithium battery pack in step five is tested for performance and safety by means of a programmable DC electronic load and a temperature sensor.

[0036] When a lithium-ion battery matching method based on battery characteristic vector is used, the capacity, voltage and internal resistance of the lithium battery are measured under normal temperature environment, and then the voltage and internal resistance of the lithium battery during normal power discharge and high power discharge under normal temperature environment are measured at the same time, and the temperature of the lithium battery during discharge is also measured, and then the lithium batteries with the same parameters are screened out to prepare for the next step of matching; lithium batteries in the same group as above are selected, all the lithium batteries are heated to a certain temperature, and the voltage and internal resistance of the lithium batteries are measured again, and then the lithium batteries are continued to be subjected to normal power discharge and high power discharge under the temperature increase environment, and the voltage and internal resistance during the discharge process are measured, and the lithium batteries with the same parameters are screened out again; lithium batteries in the same group as above are continued to be selected, and the lithium batteries All lithium batteries are cooled to a low temperature environment, and the voltage and internal resistance of the lithium batteries are measured again. Then, the lithium batteries are continued to be discharged at normal power and at high power in the low temperature environment. At the same time, the voltage and internal resistance during the discharge process are measured, and lithium batteries with the same parameters are screened out again; lithium batteries in the same group as above are selected, and all lithium batteries are placed on the surface of the vibration table, and then the lithium batteries are placed in a high vibration environment. The voltage and internal resistance of the lithium batteries are first measured, and then the voltage and internal resistance of the lithium batteries during normal discharge and high power discharge in the vibration environment are measured again, and the battery temperature is measured at the same time, and finally lithium batteries with the same parameters are obtained; finally, the lithium batteries in the same group are assembled, and after the assembly is completed, they are tested for stability and safety again, and qualified lithium battery packs can be used.

[0037] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0038] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A lithium-ion battery grouping method based on battery characteristic vector, characterized in that: The following steps are involved: Step 1: Under normal temperature, measure the capacity, voltage and internal resistance of the lithium battery. Then measure the voltage and internal resistance of the lithium battery at normal power discharge and high power discharge under normal temperature. Also measure the temperature of the lithium battery during discharge. Then select the lithium batteries with the same parameters to prepare for the next step of grouping. Step 2: Select lithium batteries in the same group, heat all lithium batteries to a certain temperature, measure the voltage and internal resistance of the lithium batteries again, and then continue to discharge the lithium batteries at normal power and high power in the heated environment, and measure the voltage and internal resistance during the discharge process, and screen out lithium batteries with the same parameters again; Step 3: Continue to select lithium batteries in the same group, cool all lithium batteries to a low temperature environment, measure the voltage and internal resistance of the lithium batteries again, and then continue to discharge the lithium batteries at normal power and high power in a low temperature environment, and measure the voltage and internal resistance during the discharge process, and screen out lithium batteries with the same parameters again; Step 4: Select lithium batteries in the same group, place all lithium batteries on the surface of the vibration table, and then place the lithium batteries in a high vibration environment. First, measure the voltage and internal resistance of the lithium batteries. Then, measure the voltage and internal resistance of the lithium batteries in the vibration environment, normal discharge and high-power discharge. At the same time, measure the battery temperature, and finally obtain lithium batteries with the same parameters. Step 5: Finally, assemble the lithium batteries in the same group. After assembly, test their stability and safety again. Qualified lithium battery packs can be used.

2. A lithium-ion battery grouping method based on battery characteristic vector according to claim 1, characterized in that: In the steps 1 to 4, a programmable DC electronic load is used to load the battery, and the voltage and internal resistance parameters are measured during the process.

3. The lithium-ion battery grouping method based on battery characteristic vector according to claim 1, characterized in that: The battery temperature in step 1 and step 4 is measured by a patch temperature sensor, and a plurality of temperature sensors need to be attached to each lithium battery.

4. A lithium-ion battery grouping method based on battery characteristic vector according to claim 1, characterized in that: The test temperature of the lithium battery in step 2 is 50°C to 60°C, and the test temperature of the lithium battery in step 3 is -25°C to -15°C.

5. The lithium-ion battery grouping method based on battery characteristic vector according to claim 1, characterized in that: The lithium battery in step 2 and the lithium battery in step 3 are both placed on a copper soaking plate, and then heated by an electric heater or cooled by an evaporator.

6. A lithium-ion battery grouping method based on battery characteristic vector according to claim 1, characterized in that: The lithium battery in step 4 needs to be mounted on the surface of the vibration table using special fasteners to prevent the lithium battery from being shaken off.

7. A lithium-ion battery grouping method based on battery characteristic vector according to claim 1, characterized in that: The lithium batteries in step five are assembled in series and connected by power lines.

8. The lithium-ion battery grouping method based on battery characteristic vector according to claim 1, characterized in that: The lithium battery pack in step 5 is tested for performance and safety by a programmable DC electronic load and a temperature sensor.

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