Zinc-iodine battery structure

Abstract

Disclosed in the invention is a zinc-iodine battery structure, which includes a housing, a cavity is formed in the housing, and a cation exchange membrane for dividing the cavity into two parts is disposed in a middle of the cavity; a glass fiber component for protecting the cation exchange membrane is disposed at a negative output end; a graphite felt impregnated with a ZnI.sub.2 solution is disposed on an outside of the glass fiber component; and the graphite felt of the negative output end is coated with Bi powder, and a graphite felt of a positive output end is coated with Sm powder. Carbon plates serving as current leading-out channels of a battery are disposed on outsides of the graphite felts; and a return flow channel is disposed between the two graphite felts. By using a homogeneous cation exchange membrane with a low electrical resistance, a problem of serious self-discharging is overcome; and by using a flow battery with an open flow system, a problem of a change in pressure caused by a change in volume during charging and discharging is effectively solved. By disposing glass fiber products on two sides of the cation exchange membrane, a dendritic crystal generated during charging is unable to reach a separator, so that short circuit caused by puncture of the separator is avoided.

Claims

1. A zinc-iodine battery structure, comprising a housing, a cavity being formed in the housing, wherein a cation exchange membrane for dividing the cavity into two parts is disposed in a middle of the cavity; a glass fiber component for protecting the cation exchange membrane is disposed at a negative output end; a graphite felt impregnated with a ZnI.sub.2 solution is disposed on an outside of the glass fiber component; the graphite felt of the negative output end is evenly coated with Bi powder less than 300 meshes, and a graphite felt of a positive output end is coated with Sm powder less than 300 meshes; carbon plates serving as current leading-out channels of a battery are disposed on outsides of the graphite felts; a return flow channel is disposed between the two graphite felts; and the return flow channel has a length-diameter ratio greater than 10 and a diameter ranging between 0.5 mm and 1.5 mm.

2. The zinc-iodine battery structure according to claim 1, wherein the housing of the battery is made of PVC plastic.

3. The zinc-iodine battery structure according to claim 1, wherein the cation exchange membrane is a homogeneous cation exchange membrane.

4. The zinc-iodine battery structure according to claim 1, wherein the glass fiber component is selected from a glass felt or a glass cloth.

5. The zinc-iodine battery structure according to claim 1, wherein a glass felt with a thickness of about 1 mm is used as the glass fiber component to protect the cation exchange membrane.

6. The zinc-iodine battery structure according to claim 1, wherein the ZnI.sub.2 solution has a molarity of 1 mol/l to 5 mol/l.

7. The zinc-iodine battery structure according to claim 1, wherein the ZnI.sub.2 solution is added with alcohol with a volume of 1/10 of a total volume.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a structure diagram of the present invention.

(2) In the drawing, 1 refers to cation exchange membrane, 2 and 3 refer to glass fiber components, 4 and 5 refer to graphite felts, 6 and 7 refer to carbon plates, and 8 refers to return flow channel.

DETAILED DESCRIPTION

(3) The technical features of the present invention are further described with reference to the drawing and the specific embodiments.

(4) As shown in FIG. 1, a zinc-iodine battery structure includes a housing, a cavity is formed in the housing, and a cation exchange membrane for dividing the cavity into two parts is disposed in a middle of the cavity; glass fiber components for protecting the cation exchange membrane are disposed on both sides of the cation exchange membrane; graphite felts impregnated with a ZnI.sub.2 solution are disposed on outsides of the glass fiber components; carbon plates serving as current leading-out channels of a battery are disposed on outsides of the graphite felts; a return flow channel is disposed between the two graphite felts; and the return flow channel has a length-diameter ratio greater than 10 and a diameter ranging between 0.5 mm and 1.5 mm, which is a key to solve a change in pressure during charging and discharging.

(5) The housing of the battery is made of PVC plastic.

(6) The cation exchange membrane is a homogeneous cation exchange membrane.

(7) The glass fiber component is selected from a glass felt.

(8) A glass felt with a thickness of about 1 mm to 10 mm is used as the glass fiber component to protect the cation exchange membrane and is used for inhibiting growth of a dendritic crystal.

(9) The graphite felts need to be processed as follows: the graphite felt of the negative electrode output end is evenly coated with ultra-fine (less than 300 meshes) Bi powder (0.5 mg/cm.sup.2 to 1.5 mg/cm.sup.2, with a total amount of about one thousandth of an amount of zinc iodide), while the graphite felt of the positive electrode output end is coated with ultra-fine (less than 300 meshes) Sm powder (0.5 mg/cm.sup.2 to 1.5 mg/cm.sup.2, with a total amount of about one thousandth of an amount of zinc iodide).

(10) The ZnI.sub.2 solution has a molarity of 1 mol/l to 5 mol/l.

(11) The ZnI.sub.2 solution is added with alcohol with a volume of 1/10 of a total volume to improve a solubility of iodine.

(12) In terms of chemical agents, ZnI.sub.2 is purified, and a positive electrode needs to be added with an analytically pure iodine I.sub.2 with an amount of twice the total molar number of zinc iodide. A concentration of the ZnI.sub.2 solution may be 1 mol/l to 5 mol/l, and anhydrous ethanol of 1/10 of a total volume of the ZnI.sub.2 solution needs to be added to the solution.

(13) A single battery is charged according to a principle of limiting a current first (a current density less than 15 mA/cm.sup.2 is recommended) and then limiting a constant voltage (a voltage less than 1.36 V is recommended). It is noted that the voltage is about 1.3 V, a storage capacity of the battery is proportional to a concentration of zinc iodide, and a storage density of 5 mol/l ZnI.sub.2 electrolyte has been close to that of a lithium ion battery. In addition, a circulation capability of charging and discharging of the battery may also reach thousands of times.

(14) We also find that the battery has no over-discharging problem, because even after over-discharging, the battery is easy to recover according to a current-limiting and voltage-limiting mode, which is beyond the reach of most secondary batteries.