Online lithium ion battery water content detection equipment and method

Abstract

The invention discloses online lithium ion battery water content detection equipment and method. A metal cavity is additionally arranged on an exhaust pipeline of a vacuum oven for baking, high-temperature gas in the vacuum oven is fed into the metal cavity through a vacuum pump, and after being mixed in the metal cavity, the high-temperature gas enters a Karl Fischer moisture measuring instrument through a pipeline with a gas flow meter for testing. According to the invention, the moisture measurement of the battery cell can be changed from an off-line test to an on-line test, so that unnecessary procedures are reduced, the automation degree of a production line is increased, and the labor cost investment is reduced; a non-sampling inspection mode is adopted, the water content of the battery cells is represented through the water content of the battery cells baked by the whole tray or even the whole drying oven, meanwhile, all detection is controlled by equipment, and the detection result is more accurate; and meanwhile, a false battery cell is not needed during testing, and non-destructive testing is realized, so that the material cost input is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion battery manufacturing, and in particular to an online lithium ion battery water content detection device and method. Background Art

[0002] At present, the manufacturing process of lithium-ion batteries has very high requirements for the water content inside the battery, which needs to be guaranteed to be below several hundred or even dozens of PPM. However, the current method of detecting the water content of lithium-ion batteries after baking is to take samples of materials from fake batteries for random inspection. Since this method is a random inspection method, the qualified water content of the battery cells at the sampling location also means that the water content of other battery cells is qualified. Secondly, this random inspection method is an irreversible destructive test, and it is necessary to ensure that at least one sample is taken from each pallet of batteries or each furnace of batteries for testing, resulting in a loss of production line costs. Finally, this method is an offline test, and the sampling location and method are all manual operations, which cannot guarantee the standardization and consistency of personnel operations.

[0003] Currently, the water content test of lithium-ion batteries after baking requires offline testing, random inspection leads to low test reliability, destructive testing leads to increased costs, and manual testing has problems such as fluctuations in test results. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an online lithium-ion battery water content detection device, including an oven, a Karl Fischer moisture meter, and a transfer mixing chamber; the oven, the transfer mixing chamber and the Karl Fischer moisture meter are connected in sequence from left to right through an exhaust duct.

[0005] Furthermore, the oven is specifically a high-temperature vacuum oven, and a gas charging valve is provided in the high-temperature vacuum oven, and the gas charging valve is used to transport nitrogen into the high-temperature vacuum oven.

[0006] Furthermore, a vacuum pump is installed above the transfer mixing chamber, and the vacuum pump is used to suck the gas in the oven into the transfer mixing chamber.

[0007] Furthermore, a heating device is provided below the transfer mixing chamber, and the heating device is used to heat the gas sucked in by the vacuum pump; the temperature range of the heating device for heating is: 90°C~100°C.

[0008] Furthermore, heat preservation cotton is arranged inside the exhaust pipe connecting the oven and the transfer mixing chamber; and a gas flow meter is arranged above the exhaust pipe connecting the transfer mixing chamber and the Karl Fischer moisture meter.

[0009] Furthermore, an air pump is installed on the right side of the Karl Fischer titrator, and the air pump is used to control the flow rate of the gas in the transfer mixing chamber into the Karl Fischer titrator.

[0010] An online lithium-ion battery water content detection method comprises the following steps: S1. placing the lithium battery in an oven for baking; S2. a vacuum pump sucks the baked gas into a transfer mixing chamber and heats it through a heating device; S3. a gas flow meter and an air pump suck the gas in the transfer mixing chamber into a Karl Fischer moisture meter for moisture measurement; S4. judging whether the moisture content of the battery cell is qualified based on the moisture measurement result.

[0011] Furthermore, in the step S2, when the temperature is increased by the temperature increasing device, the temperature is increased to 90° C. or above and stored for 3 minutes.

[0012] Furthermore, in step S3, the rate at which the gas enters the Karl Fischer titrator is specifically 100 ml / min.

[0013] The present invention provides an online lithium-ion battery water content detection device and method, which has the following beneficial effects: 1. After adopting this equipment, the moisture determination of battery cells will be changed from offline testing to online testing, which will reduce unnecessary processes, increase the degree of automation of the production line, and reduce labor cost investment.

[0014] 2. This solution is not a random inspection method. The moisture content of the battery cells is characterized by the moisture content of the battery cells baked in the entire tray or even the entire oven. At the same time, all the inspections are controlled by the equipment, and the test results are more accurate.

[0015] 3. This solution does not require fake batteries and is non-destructive testing, reducing material cost investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0017] Figure 1 This is a schematic diagram of the device structure provided by the present invention. DETAILED DESCRIPTION

[0018] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0019] The following is a detailed description of the implementation method of the present invention in conjunction with the accompanying drawings. Only some embodiments are described, not all embodiments. For the purpose of clarity, representations and descriptions that are not related to the present invention are omitted in the drawings and descriptions.

[0020] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below. Obviously, the implementation cases described are part of the embodiments of the present invention, not all of the embodiments, and cannot be understood as limiting the scope of the implementation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0021] like Figure 1 As shown, the present invention provides an online lithium-ion battery water content detection device, including an oven, a Karl Fischer moisture analyzer, and a transfer mixing chamber; the oven, the transfer mixing chamber and the Karl Fischer moisture analyzer are connected in sequence from left to right through an exhaust duct.

[0022] The oven is specifically a high-temperature vacuum oven, and a gas charging valve is provided in the high-temperature vacuum oven, and the gas charging valve is used to transport nitrogen into the high-temperature vacuum oven.

[0023] A vacuum pump is installed above the transfer mixing chamber, and the vacuum pump is used to suck the gas in the oven into the transfer mixing chamber.

[0024] A heating device is provided below the transfer mixing chamber, and the heating device is used to heat the gas sucked in by the vacuum pump; the temperature range of the heating device for heating is: 90°C~100°C.

[0025] The exhaust pipe connecting the oven and the transfer mixing chamber is provided with heat insulation cotton inside; and the exhaust pipe connecting the transfer mixing chamber and the Karl Fischer moisture meter is provided above the exhaust pipe.

[0026] An air pump is installed on the right side of the Karl Fischer titrator, and the air pump is used to control the flow rate of the gas in the transfer mixing chamber into the Karl Fischer titrator.

[0027] An online lithium-ion battery water content detection method comprises the following steps: S1. Place the lithium battery in an oven for baking. The high-temperature vacuum oven uses a cycle baking method of heating, vacuuming, nitrogen filling, heat preservation, and vacuuming for baking. After the last vacuuming and nitrogen filling, the nitrogen containing water vapor is discharged into the exhaust pipe, and the pipe is insulated with thermal insulation cotton.

[0028] S2. The vacuum pump sucks the baked gas into the transfer mixing chamber and heats it through the heating device. The gas is sucked into the cavity through the vacuum pump, and the cavity and the heating device (such as a heating plate) are heated to 90°C or above and stored for 3 minutes.

[0029] S3. The gas in the transfer mixing chamber is sucked into the Karl Fischer moisture analyzer through a gas flow meter and an air pump for moisture determination: The gas in the cavity is controlled by a gas flow meter to enter the Karl Fischer moisture analyzer through a pipeline at a frequency of less than 100 ml / min.

[0030] S4. Determine whether the moisture content of the battery cell is qualified based on the moisture measurement results.

[0031] Example: For a 100Ah ternary lithium-ion battery production line, the specific detection method includes: Formulate process parameters, use 50 trays of battery cells, and adopt process parameters of 90℃, vacuum degree -95kPa, single vacuum pressure holding time 1 hour, nitrogen filling time 15min, and vacuum extraction time 15min. Cycle vacuum extraction, pressure holding, and nitrogen filling. The moisture content of the gas discharged each time is measured. The data of the 50 trays must be recorded each time the moisture content is measured.

[0032] The moisture measurement results of each tray show a downward trend. After the downward trend stabilizes, the distribution of moisture measurement results is recorded, and the upper limit is taken as the process standard based on the 3sigma of the data distribution.

[0033] In the normal production process, cells with water content lower than the standard value are normal cells and flow into the next process. The remaining abnormal cells have their baking time increased and are retested. They can flow into the next process only after passing the test.

[0034] In the present invention, the moisture determination of the battery cell can be changed from an offline test to an online test, thereby reducing unnecessary processes, increasing the degree of automation of the production line, and reducing labor cost investment; the present invention adopts a non-sampling method, and characterizes the water content of the battery cell by the moisture content of the battery cells baked in a whole tray or even a whole oven, and all the detection is controlled by the equipment, so the test result is more accurate; at the same time, no dummy battery cells are required when testing in the present invention, and non-destructive testing is performed, thereby reducing material cost investment.

[0035] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. An online lithium-ion battery water content detection device, comprising an oven and a Karl Fischer moisture meter, characterized in that: It also includes a transfer mixing chamber; the oven, the transfer mixing chamber and the Karl Fischer moisture analyzer are connected in sequence from left to right through an exhaust duct.

2. The online lithium-ion battery water content detection device according to claim 1, characterized in that: The oven is specifically a high-temperature vacuum oven, and a gas charging valve is provided in the high-temperature vacuum oven, and the gas charging valve is used to transport nitrogen into the high-temperature vacuum oven.

3. The online lithium-ion battery water content detection device according to claim 1, characterized in that: A vacuum pump is installed above the transfer mixing chamber, and the vacuum pump is used to suck the gas in the oven into the transfer mixing chamber.

4. The online lithium-ion battery water content detection device according to claim 3, characterized in that: A heating device is provided below the transfer mixing chamber, and the heating device is used to heat the gas sucked in by the vacuum pump; the temperature range of the heating device for heating is: 90°C~100°C.

5. The online lithium-ion battery water content detection device according to claim 1, characterized in that: The exhaust pipe connecting the oven and the transfer mixing chamber is provided with heat insulation cotton inside; and the exhaust pipe connecting the transfer mixing chamber and the Karl Fischer moisture meter is provided above the exhaust pipe.

6. The online lithium-ion battery water content detection device according to claim 1, characterized in that: An air pump is installed on the right side of the Karl Fischer titrator, and the air pump is used to control the flow rate of the gas in the transfer mixing chamber into the Karl Fischer titrator.

7. An online lithium-ion battery water content detection method, based on the online lithium-ion battery water content detection device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Place the lithium battery in an oven for baking; S2. The vacuum pump sucks the baked gas into the transfer mixing chamber and heats it through the heating device; S3. The gas in the transfer mixing chamber is sucked into the Karl Fischer moisture meter through the gas flow meter and the air pump for moisture measurement; S4. Determine whether the moisture content of the battery cell is qualified based on the moisture measurement results.

8. The method for detecting water content of an online lithium-ion battery according to claim 7, characterized in that: In the step S2, when the temperature is increased by the temperature increasing device, the temperature is increased to 90° C. or above and stored for 3 minutes.

9. The method for detecting water content of an online lithium-ion battery according to claim 7, characterized in that: In the step S3, the rate at which the gas enters the Karl Fischer titrator is specifically 100 ml / min.

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