Self-exothermic positive electrode material for thermal battery and preparation method thereof

Abstract

This invention relates to a self-exothermic thermal battery cathode material and its preparation method, solving the problem that current methods for maintaining the thermal life of thermal batteries mainly rely on insulation materials with low thermal conductivity to delay heat dissipation. While this extends the thermal life, the heat loss is irreversible. The cathode powder comprises cathode material, an ionic conductive agent, and a lithium-ionizing agent, with the following weight percentages: cathode material 60%–90%, ionic conductive agent 8%–35%, and lithium-ionizing agent 1%–5%. The cathode powder is obtained by mechanical mixing in a dry environment followed by high-temperature vacuum treatment. The preparation method of the self-exothermic thermal battery cathode material involves adding cathode powder and LiSi alloy powder in proportion to a container and mechanically mixing them under dry environmental protection. The material of this invention exhibits stable performance at room temperature and can be stored for a long time. When the thermal battery is activated, an exothermic reaction occurs at high temperatures, compensating for some of the heat lost by the thermal battery and extending its thermal life.

Description

Technical Field

[0001] This invention belongs to the field of thermal battery technology and relates to a self-exothermic thermal battery cathode material and its preparation method. Background Technology

[0002] As is well known, the operating time of a thermal battery is affected by both capacity and thermal life. Thermal life refers to the duration during which the temperature required for the thermal battery to operate normally drops to an unacceptable level. Under the same capacity, its operating time is affected by thermal life.

[0003] Currently, the main method to maintain the thermal life of thermal batteries is to use insulation materials with low thermal conductivity to slow down the heat dissipation of the thermal battery. Although this method extends the thermal life of the thermal battery, the heat loss is irreversible. Summary of the Invention

[0004] This invention provides a self-exothermic thermal battery cathode material and its preparation method, which solves the problem that current methods for maintaining the thermal life of thermal batteries mainly involve using insulation materials with low thermal conductivity to delay heat dissipation. Although this extends the thermal life of the thermal battery, the heat loss is irreversible.

[0005] The material is stable at room temperature and can be stored for a long time. When the thermal battery is activated, it can undergo an exothermic reaction at high temperature, which can extend the thermal battery's thermal life by compensating for some of the heat lost by the thermal battery.

[0006] This invention is achieved through the following technical solutions: A self-exothermic thermal battery cathode material comprises cathode powder and LiSi alloy powder, with the following weight percentages: cathode powder 94%–98.5% and LiSi alloy powder 1.5%–6%.

[0007] Furthermore, the positive electrode powder comprises a positive electrode material, an ionic conductive agent, and a lithiation agent, with the following weight percentages: 60%–90% positive electrode material, 8%–35% ionic conductive agent, and 1%–5% lithiation agent; the positive electrode powder is obtained by mechanical mixing in a dry environment followed by high-temperature vacuum treatment.

[0008] Furthermore, the positive electrode material is one or more of FeS2, CoS2, and FeCoS2.

[0009] Furthermore, the ionic conductive agent is a eutectic salt of KCl-LiCl, LiF-LiCl-LiBr, LiCl-LiBr-KBr, or LiF-LiBr-KBr.

[0010] Furthermore, the lithiating agent is LiO2 or LiSi alloy powder.

[0011] A method for preparing a self-exothermic thermal battery cathode material involves adding cathode powder and LiSi alloy powder in proportion to a container and mechanically mixing them under dry environmental protection.

[0012] The beneficial effects of the self-exothermic thermal battery cathode material described in this invention are: 1. The positive electrode material of this self-exothermic thermal battery is made by mechanically mixing positive electrode powder and LiSi alloy in a dry environment. The operation is simple and the cost is low.

[0013] 2. The positive electrode material of this self-exothermic thermal battery can generate heat through self-reaction, thereby extending the thermal life of the thermal battery and thus extending the working time of the thermal battery. 3. The amount of LiSi alloy powder added to the positive electrode material of this self-exothermic thermal battery is relatively small, which has no impact on the overall capacity and safety of the thermal battery. Attached Figure Description

[0014] Figure 1 The discharge curve of a thermal battery made with positive electrode powder; Figure 2 The discharge curve of the thermal battery obtained in Example 1 of this invention is shown. Figure 3 The discharge curve of the thermal battery obtained in Example 2 of this invention is shown. Figure 4 The discharge curve of the thermal battery obtained in Example 3 of this invention is shown. Detailed Implementation To further understand the content, features, and effects of this invention, the following embodiments are provided and described in detail below: Example 1: 94g of positive electrode powder and 6g of LiSi alloy powder were added to a container and mechanically mixed under dry conditions to obtain the No. 1 self-exothermic thermal battery positive electrode material, which was then bottled and stored for later use. In this embodiment, the positive electrode powder contained 40% FeS2, 40% CoS2, 18% ionic conductive agent, and 2% LiO2. The ionic conductive agent used was a eutectic salt of LiF-LiCl-LiBr.

[0015] Example 2: 98.5g of positive electrode powder and 1.5g of LiSi alloy powder were added to a container and mechanically mixed under dry conditions to obtain the positive electrode material for a self-exothermic thermal battery (No. 2). The mixture was then bottled and stored for later use. In this embodiment, the positive electrode powder contained 40% FeS2, 40% CoS2, 18% ionic conductive agent, and 2% LiO2. The ionic conductive agent used was a eutectic salt of LiF-LiCl-LiBr.

[0016] Example 3: 98.5g of positive electrode powder and 1.5g of LiSi alloy powder were added to a container and mechanically mixed under dry conditions to obtain the positive electrode material for a self-exothermic thermal battery (No. 3). The mixture was then bottled and stored for later use. In this embodiment, the positive electrode powder contained 80% FeCoS2, 18% ionic conductive agent, and 2% LiO2.

[0017] Experimental Example 1: Pour heating material into a φ24mm mold and level it with a scraper. Then pour in conventional positive electrode powder and level it. Next, pour in separating powder and level it. Cover with the mold and pre-press it once with a press. Then remove the mold and place a φ24mm×21mm asbestos ring on the separating powder with tweezers. Then put the negative electrode material into the asbestos ring, cover with the mold, and press it into shape with a press. After demolding, you will get a #0 single cell.

[0018] Experimental Example 2: Heating material is introduced into a φ24mm mold and leveled with a scraper. Then, the positive electrode material of the self-exothermic thermal battery prepared in any of the embodiments 1-3 is randomly poured in and leveled. Next, the separating powder is poured in and leveled. The mold is then covered and pre-pressed once with a press. The mold is then removed, and a φ24mm×21mm asbestos ring is placed on the separating powder with tweezers. The negative electrode material is then placed into the asbestos ring, the mold is covered, and the material is pressed into shape with a press. After demolding, cells #1, #2, and #3 are obtained respectively.

[0019] Fifteen of the aforementioned individual cells were connected in series and housed in a φ30mm×50mm stainless steel battery casing. Following different test examples, they were labeled as 0#, 1#, 2#, and 3# thermal batteries, respectively. A constant current discharge of 2A was performed using conventional methods, with a cutoff voltage of 24V. The operating time of each thermal battery was recorded, and the test results are shown in Table 1. Table 1 shows that the self-exothermic thermal battery cathode material significantly extends the operating time of the thermal battery (by more than 40 seconds) compared to the conventional cathode material.

[0020] Table 1 Summary of Electrical Performance Test Results thermal battery number Working hours (s) 0# 152 1# 193 2# 198 3# 205 The embodiments described above are merely illustrative of the technical features and preferred embodiments of the present invention. For those skilled in the art, several similar modifications and improvements can be made without departing from the inventive concept of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A self-exothermic thermal battery cathode material, characterized in that: It includes cathode powder and LiSi alloy powder, with a weight percentage of 94% to 98.5% for cathode powder and 1.5% to 6% for LiSi alloy powder.

2. The self-exothermic thermal battery cathode material according to claim 1, characterized in that: The cathode powder comprises cathode material, ion-conducting agent and lithiation agent, with the following weight percentages: cathode material 60% to 90%, ion-conducting agent 8% to 35%, and lithiation agent 1% to 5%.

3. The self-exothermic thermal battery cathode material according to claim 2, characterized in that: Positive electrode powder is obtained by mechanical mixing in a dry environment followed by high-temperature vacuum treatment.

4. The positive electrode material of a self-exothermic thermal battery according to claim 2, characterized in that: The cathode material is one or more of FeS2, CoS2, and FeCoS2.

5. The self-exothermic thermal battery cathode material according to claim 2, characterized in that: The ionic conductive agent is a eutectic salt of KCl-LiCl, LiF-LiCl-LiBr, LiCl-LiBr-KBr, or LiF-LiBr-KBr.

6. The positive electrode material of a self-exothermic thermal battery according to claim 2, characterized in that: The lithiating agent is LiO2 or LiSi alloy powder.

7. A method for preparing a self-exothermic thermal battery cathode material as described in any one of claims 1-6, characterized in that: Positive electrode powder and LiSi alloy powder are added to the container in proportion and mechanically mixed under dry environmental protection.

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