GB/T 37204-2018Electrolyte for vanadium flow battery (English PDF)

3.1 Product classification

The products are divided into three varieties according to the different valence states of vanadium ions. 3-valent electrolyte, 3.5-valent electrolyte, and 4-valent electrolyte.

Each variety is divided into two levels based on impurity content. first-class products and second-class products.

3.2 Main component content

The vanadium content, sulfate content, and ratio of vanadium ions in different valence states in the product shall comply with the requirements in Table 1.

3.3 Impurity element content

The content of impurity elements in the product shall comply with the requirements in Table 2. If the purchaser has other requirements for the impurity element content of the product, please indicate it in the order sheet (or contract).

3.4 Additive

A certain number of additives are allowed to be added to the electrolyte. The type and number of additives shall be specified in the order sheet (or contract). Report as actual measured value.

3.5 Insoluble impurities

The product shall be free of insoluble impurities.

3.6 Physical properties

The supplier shall provide electrolyte conductivity and viscosity indicators in the quality certificate and report them as actual measured values.

4.1 Main component content

The analysis of vanadium content and the ratio of vanadium ions in different valence

4.2 Impurity element content

4.3 Additive

Additive analysis is carried out according to the supplier's current method. If there are any objections, they will be resolved through negotiation between the supplier and the purchaser.

4.4 Insoluble impurities

4.4.1 The detection of insoluble impurities is carried out in accordance with the relevant regulations of GB/T 11901-1989.

4.5 Physical properties

4.5.1 The conductivity testing is carried out in accordance with the provisions of 7.3 and 7.5 in GB/T 6908-2008.

4.5.2 The viscosity is tested in accordance with the provisions of Chapter 2 of GB/T 10247-2008. Use the Ubbelohde viscometer specified in A.3 of Annex A of GB/T 10247-2008. Depending on the actual viscosity, select a viscometer with size 0C, 0B or 1 specified in Table A.3 in Annex A of GB/T 10247-2008 for measurement.

5.1 Inspection and acceptance

5.1.1 The product shall be inspected by the supplier to ensure that the product quality complies with the provisions of this Standard and the order sheet (or contract). A quality certificate shall be filled out.

5.3 Inspection item

Before each batch of products leaves the factory, the main component content, impurity element content, additive content, insoluble impurities, and physical properties shall be inspected.

5.4 Sampling

5.4.1 To collect the samples for testing the main component content, impurity element content, additive content and physical properties, determine the number of sampling units in accordance with the provisions of GB/T 6678.

5.5 Judgment of inspection results

5.5.1 If the content of the main ingredients fails to pass the inspection, the batch of products will be deemed to be unqualified.

5.5.2 If the impurity element content test fails, the batch of products will be deemed unqualified.

5.5.3 If the test of insoluble impurities fails, the batch of products will be deemed unqualified.

6.1 Marks

The following marks (or labels) shall be printed on the outer packaging of the electrolyte.

6.2 Packaging, transportation and storage

6.2.1 Products shall be stored in plastic containers that are resistant to sulfuric acid corrosion. The volume meets the batch requirements. Seal with a sulfuric acid-resistant plastic cap.

6.2.3 The transportation and storage temperature range of the product is. -15°C~40°C. Avoid long-term direct sunlight.

6.2.4 When needed, nitrogen can be injected into the container as a protective gas.

6.3 Quality certificate

Each batch of products shall be accompanied by a product quality certificate, indicating.

A.1 Scope

This appendix specifies the method for determination of vanadium ion content in vanadium electrolyte. The measurement range of positive trivalent vanadium ion content is 0.00 mol/L~2.50 mol/L. The measurement range of positive tetravalent vanadium ion content is 0.00 mol/L~2.50 mol/L.

A.2 Principle

There are two adjacent valence states of vanadium ions in the electrolyte solution.

Based on the redox reaction between potassium permanganate and low-valent vanadium, in a phosphate buffer solution, the electrolyte sample is titrated with a standard titration solution of potassium permanganate, and the low-valent vanadium ions are gradually oxidized until they are pentavalent. Each sudden jump in potential corresponds to a change in the valence state of vanadium. According to the consumed volume of potassium permanganate standard solution corresponding to the potential jump point, calculate the content of vanadium ions in each valence state and total vanadium. […]