Battery cover plate assembly and manufacturing method thereof

Abstract

The invention relates to the field of batteries, and provides a battery cover plate assembly and a manufacturing method thereof. The battery cover plate assembly comprises a cover plate, a groove is formed in the cover plate, a first pole hole is formed in the bottom of the groove, the negative pole comprises a lower negative pole and an upper negative pole which are connected, part of the lower negative pole is inserted into the first pole hole, at least part of the upper negative pole is located in the groove, an upper negative plastic part is arranged between the upper negative pole and the groove, and the upper negative plastic part is inserted into the first pole hole. And the cathode upper pole and the cover plate are insulated. The first high-temperature insulating part is embedded in the negative electrode upper post, the upper negative electrode plastic part and the cover plate, and the first high-temperature insulating part is made of a non-expansive high-temperature insulating material. The battery cover plate assembly is ensured to be free of direct short circuit of the positive electrode and the negative electrode of the battery due to the obstruction of the first high-temperature insulation assembly even if the upper plastic part and the lower plastic plate are melted due to high temperature at a high temperature, thereby avoiding ignition of the battery and ignition of combustible gas, and further avoiding fire and explosion caused by thermal runaway of the battery and a module thereof.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cover assembly and a manufacturing method thereof. Background Art

[0002] An important reason for sparks after a lithium-ion battery energy storage system fails is the short circuit of the battery body. At present, the cover plate above the battery body is made of aluminum, and the battery pole is made of copper and aluminum metal. The insulation of the battery pole and the aluminum cover plate uses insulating gaskets and insulating sealing rings, and the insulating gaskets and insulating sealing rings are made of plastic, rubber and other materials. When the battery does not have thermal runaway, the insulating gaskets and insulating sealing rings can play a good insulating role and avoid short circuits between the positive and negative poles of the battery.

[0003] However, the temperature resistance of insulating gaskets and insulating sealing rings generally does not exceed 300°C. The maximum temperature during thermal runaway of the battery reaches over 500°C. At this time, the insulating gasket and insulating sealing ring will melt due to the high temperature generated by the thermal runaway of the battery. After the insulating gasket and insulating sealing ring melt, the positive and negative poles of the battery and the aluminum cover are directly connected, forming a short circuit, which is very easy to generate sparks during short-circuit overcharging and ignite combustible gases. Therefore, there is an urgent need for a battery cover that can avoid the insulation damage of the positive and negative poles of the battery to generate sparks, which may ignite the combustible gas of thermal runaway and cause fire and explosion. Summary of the invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present application provides a battery cover assembly and a manufacturing method thereof.

[0005] In a first aspect, an embodiment of the present application provides a battery cover assembly, comprising:

[0006] A cover plate, wherein a groove is formed on the cover plate, and a first pole hole is formed at the bottom of the groove;

[0007] A negative electrode column, comprising a negative electrode lower electrode column and a negative electrode upper electrode column connected to each other, wherein part of the negative electrode lower electrode column is inserted into the first electrode column hole, and at least part of the negative electrode upper electrode column is located in the groove;

[0008] An upper negative electrode plastic part is provided between the negative electrode upper pole and the groove to insulate the negative electrode upper pole and the cover plate;

[0009] The first high-temperature insulating component is embedded in the negative electrode upper pole, the upper negative electrode plastic component and the cover plate. The first high-temperature insulating component is used to support the negative electrode upper pole and the upper negative electrode plastic component to prevent the negative electrode upper pole from contacting the cover plate after the upper negative electrode plastic component is deformed by heat. The first high-temperature insulating component adopts a non-expansion type high-temperature insulating material.

[0010] According to an embodiment of the first aspect of the present application, the first high-temperature insulating component is in a columnar structure or an annular structure, and the material of the first high-temperature insulating component includes at least one of silicate glass, silicate ceramics, mica, silicate cement, aluminum oxide, zirconium oxide, zinc oxide, silicon nitride, boron carbide, titanium oxide, silicon carbide, boron carbide, cerium carbide, molybdenum carbide, niobium carbide, zirconium carbide, titanium carbide, vanadium carbide, tungsten carbide, tantalum carbide, silicon nitride, boron nitride, aluminum nitride, titanium diboride, and zirconium diboride.

[0011] According to an embodiment of the first aspect of the present application, the battery cover assembly also includes a plastic plate and an insulating sealing ring, the plastic plate is stacked and distributed on the cover plate and is connected to the side of the cover plate away from the negative upper pole, a second pole hole is formed on the plastic plate, the negative lower pole is inserted into the second pole hole, and the insulating sealing ring is provided between the inner wall of the first pole hole, the inner wall of the second pole hole and the negative lower pole.

[0012] According to an embodiment of the first aspect of the present application, the negative electrode lower column includes a large end and a small end, the small end passes through the second pole hole and the first pole hole and is connected to the negative electrode upper pole, and the large end abuts against the plastic plate;

[0013] A second high-temperature insulating member is disposed on the periphery of the insulating sealing ring. The second high-temperature insulating member is annular or columnar and is located between the inner wall of the second pole hole and the insulating sealing ring.

[0014] According to an embodiment of the first aspect of the present application, the inner ring of the second high-temperature insulating member in contact with the insulating sealing ring is made of non-expanding high-temperature insulating material, and the outer ring of the second high-temperature insulating member in contact with the inner wall of the second pole hole is made of expanding high-temperature insulating material.

[0015] According to an embodiment of the first aspect of the present application, the expandable high-temperature insulation material includes an expandable base material, a foaming aid, a foaming catalyst and a thickener.

[0016] According to an embodiment of the first aspect of the present application, the expansion base material is phenolic resin or pentaerythritol;

[0017] And / or, the foaming aid is dicyandiamide or polyamide;

[0018] And / or, the foaming catalyst is high-polymerization degree ammonium polyphosphate;

[0019] And / or, the thickener is fumed silica or silicone gel.

[0020] According to an embodiment of the first aspect of the present application, the battery cover assembly also includes a positive electrode column and an upper positive electrode plastic part, the positive electrode column includes a positive upper electrode column and a positive lower electrode column connected to each other, and two grooves are provided on the cover plate, one of the grooves is provided with the positive upper electrode column, and the other groove is provided with the negative upper electrode column, the positive lower electrode column passes through the bottom of the groove and is connected to the positive upper electrode column, and the upper positive electrode plastic part is provided between the positive upper electrode column and the groove.

[0021] According to an embodiment of the first aspect of the present application, the upper positive electrode plastic part and the upper negative electrode plastic part are made of polyphenylene sulfide material.

[0022] In a second aspect, an embodiment of the present application provides a method for manufacturing a battery cover assembly, comprising: conducting a simulation experiment on a battery to obtain the maximum tolerance temperature of multiple components of the battery cover assembly when the battery is in thermal runaway, wherein the temperature of the upper negative electrode plastic part is higher than the temperature of other components when the battery is in thermal runaway;

[0023] A first high-temperature insulating component is arranged on the negative pole, and the first high-temperature insulating component is embedded in the negative upper pole, the upper negative plastic part and the cover plate, and the first high-temperature insulating component is used to support the negative upper pole and the upper negative plastic part to prevent the negative upper pole from contacting the cover plate after the upper negative plastic part is deformed by heat;

[0024] Design insulation damage prevention materials and battery cover components based on key heat resistance parameters.

[0025] Compared with the prior art, the technical solution provided by the embodiments of the present application has the following advantages:

[0026] The battery cover plate assembly and its manufacturing method provided in the embodiment of the present application are provided with a first high-temperature insulating member between the negative upper pole, the upper negative plastic part and the cover plate, the first high-temperature insulating member is used to support the negative upper pole and the upper negative plastic part, so as to avoid the contact between the negative upper pole and the cover plate after the upper negative plastic part is deformed by heat, and when the battery is in thermal runaway, after the upper negative plastic part is melted by heat, the first high-temperature insulating member is supported between the negative upper pole and the cover plate so that the negative upper pole and the cover plate have a gap and will not contact and conduct, so as to avoid the contact and conduction between the negative upper pole and the cover plate of the battery when the battery is in thermal runaway, resulting in a short circuit after the negative pole and the positive pole are connected. It is ensured that the battery cover plate assembly is under high temperature, even if the upper plastic part and the lower plastic plate are melted by high temperature, the direct short circuit between the positive and negative poles of the battery will not be caused due to the barrier of the first high-temperature insulating member, so as to avoid the battery ignition and ignition of combustible gas, thereby avoiding the fire and explosion of the battery and its module in thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0028] In order to more clearly illustrate the embodiments of the present application 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a schematic diagram of the exploded structure of the battery cover assembly described in an embodiment of the present application;

[0030] Figure 2 This is a schematic diagram of the three-dimensional structure of the battery cover assembly described in an embodiment of the present application;

[0031] Figure 3 for Figure 2 A schematic diagram of the local structure of the negative electrode column;

[0032] Figure 4 This is a schematic diagram of a method for manufacturing a battery cover assembly according to an embodiment of the present application;

[0033] Figure 5 This is a flow chart of the method for manufacturing the battery cover assembly described in an embodiment of the present application.

[0034] Among them, 1. cover plate; 11. first pole hole; 2. negative lower pole; 3. negative upper pole; 4. upper negative plastic part; 5. first high-temperature insulating part; 6. plastic plate; 61. second pole hole; 7. insulating sealing ring; 8. second high-temperature insulating part; 91. upper positive plastic part; 92. positive upper pole; 93. positive lower pole. DETAILED DESCRIPTION

[0035] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only part of the embodiments of the present application, rather than all of the embodiments.

[0037] An important reason for sparks after a lithium-ion battery energy storage system fails is the short circuit of the battery body. At present, the cover plate above the battery body is made of aluminum, and the battery pole is made of copper and aluminum metal. The insulation of the battery pole and the aluminum cover plate uses insulating gaskets and insulating sealing rings, and the insulating gaskets and insulating sealing rings are made of plastic, rubber and other materials. When the battery does not have thermal runaway, the insulating gaskets and insulating sealing rings can play a good insulating role and avoid short circuits between the positive and negative poles of the battery.

[0038] However, the temperature tolerance of insulating gaskets and insulating seals generally does not exceed 300°C. The highest temperature during battery thermal runaway reaches over 500°C. At this time, the insulating gaskets and insulating seals will melt due to the high temperature generated by the thermal runaway of the battery. After the insulating gaskets and insulating seals melt, the positive and negative poles of the battery and the aluminum cover are directly connected, forming a short circuit, which is very easy to generate sparks during short-circuit overcharging and ignite combustible gases.

[0039] In view of this, if Figures 1 to 3 As shown, the embodiment of the present application provides a battery cover assembly, including a cover 1, a negative pole, an upper negative pole plastic part 4 and a first high-temperature insulating part 5. A groove is formed on the cover 1, and a first pole hole 11 is formed at the bottom of the groove. The negative pole includes a negative lower pole 2 and a negative upper pole 3 connected to each other. Part of the negative lower pole 2 is inserted into the first pole hole 11, and at least part of the negative upper pole 3 is located in the groove. An upper negative pole plastic part 4 is provided between the negative upper pole 3 and the groove to insulate the negative upper pole 3 from the cover 1. The first high-temperature insulating part 5 is embedded in the negative upper pole 3, the upper negative pole plastic part 4 and the cover 1. The first high-temperature insulating part 5 is used to support the negative upper pole 3 and the upper negative pole plastic part 4 to prevent the negative upper pole 3 from contacting the cover 1 after the upper negative pole plastic part 4 is deformed by heat. The first high-temperature insulating part 5 adopts a non-expansion type high-temperature insulating material.

[0040] The embodiment of the present application provides a battery cover plate assembly, by arranging a first high-temperature insulating member 5 between the negative upper pole 3, the upper negative plastic member 4 and the cover plate 1, the first high-temperature insulating member 5 is used to support the negative upper pole 3 and the upper negative plastic member 4, so as to avoid the contact between the negative upper pole 3 and the cover plate 1 after the upper negative plastic member 4 is deformed by heat, and when the battery is thermally runaway, after the upper negative plastic member 4 is heated and melted, the first high-temperature insulating member 5 is supported between the negative upper pole 3 and the cover plate 1 so that the negative upper pole 3 and the cover plate 1 are left with a gap and will not contact and conduct, so as to avoid the contact and conduction between the negative upper pole 3 and the cover plate 1 of the battery when the battery is thermally runaway, resulting in a short circuit after the negative pole and the positive pole are connected. It is ensured that the battery cover plate assembly is at high temperature, even if the upper plastic member and the lower plastic plate are melted due to high temperature, the direct short circuit between the positive and negative poles of the battery will not be caused due to the barrier of the first high-temperature insulating member, so as to avoid the battery ignition and ignition of combustible gas, thereby avoiding the thermal runaway fire and explosion of the battery and its module.

[0041] In some embodiments, the first high temperature insulating member 5 is in a columnar structure or an annular structure, for example, the first high temperature insulating member 5 is in a cylindrical shape, a square column shape, a circular ring shape or a square ring shape, etc. A plurality of first high temperature insulating members 5 are provided, and the plurality of first high temperature insulating members 5 can be in one shape or multiple shapes at the same time. The plurality of first high temperature insulating members 5 are distributed at intervals along the circumference of the negative upper pole 3, and the non-expanding high temperature insulating material includes at least one of silicate glass, silicate ceramics, mica, silicate cement, aluminum oxide, zirconium oxide, zinc oxide, silicon nitride, boron carbide, titanium oxide, silicon carbide, boron carbide, cerium carbide, molybdenum carbide, niobium carbide, zirconium carbide, titanium carbide, vanadium carbide, tungsten carbide, tantalum carbide, silicon nitride, boron nitride, aluminum nitride, titanium diboride, and zirconium diboride. The plurality of first high temperature insulating members 5 distributed at intervals along the circumference of the negative upper pole 3 can better and more evenly support the negative upper pole 3, so that no part of the negative upper pole 3 will contact the cover plate 1.

[0042] In some embodiments, the battery cover assembly also includes a plastic plate 6 and an insulating sealing ring 7. The plastic plate 6 is stacked with the cover 1 and connected to the side of the cover 1 facing away from the negative upper pole 3. A second pole hole 61 is formed on the plastic plate 6. The negative lower pole 2 is inserted into the second pole hole 61. An insulating sealing ring 7 is provided between the inner wall of the first pole hole 11 and the inner wall of the second pole hole 61 and the negative lower pole 2. The plastic plate 6 is located between the cover 1 and the battery cell. The plastic plate 6 is used for electrical conduction between the insulating cover 1 and the battery cell.

[0043] The plastic plate 6 can be made of one or more combinations of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polyperfluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), and polyaryletherketone (PAEK). The insulating seal ring 7 can be made of one or more combinations of silicone rubber, fluorosilicone rubber, polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polyperfluoroethylene propylene (FEP), and polyvinylidene fluoride (PVDF).

[0044] In some embodiments, Figure 2 and Figure 3As shown, the negative lower column includes a large end and a small end. The small end passes through the second column hole 61 and the first column hole 11 and is connected to the negative upper column 3. The large end abuts against the plastic plate 6. The plastic plate 6 is used to insulate the contact and conduction between the large end and the cover plate 1. A second high-temperature insulating member 8 is provided on the periphery of the insulating seal ring 7. The second high-temperature insulating member 8 is in a columnar structure or an annular structure. For example, the second high-temperature insulating member 8 is in a cylindrical, square column, circular ring or square ring shape. The second high-temperature insulating member 8 is located between the inner wall of the second column hole 61 and the insulating seal ring 7. When the battery thermally runs away, after the insulating seal ring 7 is heated and melted, the second high-temperature insulating member 8 is used to insulate the negative lower column 2 from the cover plate 1 to prevent the cover plate 1 from contacting the negative lower column 2 and causing a short circuit between the positive column and the negative column.

[0045] In some embodiments, the inner ring of the second high temperature insulating member 8 in contact with the insulating sealing ring 7 is made of non-expandable high temperature insulating material, and the outer ring of the second high temperature insulating member 8 in contact with the inner wall of the second pole hole 61 is made of expandable high temperature insulating material. When the second high temperature insulating member 8 is heated, the inner ring plays a supporting role, and the outer ring made of expandable high temperature insulating material expands and fills the surrounding gaps after being heated, achieving a good insulation effect. The non-expandable high temperature insulating material of the inner ring is composed of 100% alumina material. The second high temperature insulating member 8 is composed of a mixture of 60% non-expandable high temperature insulating material and 40% expandable high temperature insulating material.

[0046] In some embodiments, the intumescent high temperature insulating material includes an intumescent base material, a foaming aid, a foaming catalyst and a thickener. In some embodiments, the intumescent base material can be a combination of one or more of starch, glucose, maltose, phenolic resin, epoxy resin, polyethylene resin, polypropylene resin, polymethyl methacrylate, ethylene-vinyl acetate copolymer, pentaerythritol, dipentaerythritol, and trimerpentaerythritol, preferably a phenolic resin or trimerpentaerythritol. The foaming aid can be a combination of one or more of melamine, polyamide, urea, melamine, dicyandiamide, dicyandiamide formaldehyde resin, boric acid amine, and semicarbazide, preferably dicyandiamide or polyamide. The foaming catalyst can be a combination of one or more of polyphosphoric acid, phosphoramide, phosphate, high-polymerization ammonium polyphosphate, and trichloride phosphorus, preferably high-polymerization ammonium polyphosphate. The thickener can be a combination of one or more of molecular sieves, silica gel, diatomaceous earth, fumed silica, and bentonite, preferably fumed silica or silica gel.

[0047] In some embodiments, the battery cover assembly also includes a positive electrode column and an upper positive electrode plastic part 91, the positive electrode column includes a positive upper electrode column 92 and a positive lower electrode column 93 connected to each other, and there are two grooves on the cover 1, one groove is provided with a positive upper electrode column 92, and the other groove is provided with a negative upper electrode column 3, the positive lower electrode column 93 passes through the bottom of the groove and is connected to the positive upper electrode column 92, an upper positive electrode plastic part 91 is provided between the positive upper electrode column 92 and the groove, and the positive electrode plastic part is used to insulate the electrical conduction between the positive upper electrode column 92 and the cover 1.

[0048] The upper positive electrode plastic part 91 and the upper negative electrode plastic part 4 can be made of one or more combinations of polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polyperfluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), polyaryletherketone (PAEK), polyimide (PI), semi-aromatic nylon (PPA), fully aromatic nylon (PARA), and aliphatic polyamide (PA46), preferably polyphenylene sulfide material.

[0049] Another embodiment of the present application provides a method for manufacturing a battery cover assembly, such as Figure 4 and Figure 5 As shown, it includes: conducting a simulation experiment on the battery to obtain the maximum tolerance temperature of multiple components of the battery cover assembly when the battery is in thermal runaway, wherein the temperature of the upper negative electrode plastic part 4 is higher than the temperature of other components when the battery is in thermal runaway. A first high-temperature insulation component is arranged on the negative pole, and the first high-temperature insulation component is embedded in the negative upper pole 3, the upper negative pole plastic part 4 and the cover 1. The first high-temperature insulation part 5 is used to support the negative upper pole 3 and the upper negative pole plastic part 4 to prevent the upper negative pole 3 from contacting the cover 1 after the upper negative pole plastic part 4 is deformed by heat. Design insulation damage-resistant materials and battery cover assemblies based on key heat-resistant parameters. There is no order for the above steps, as long as the required conditions can be achieved.

[0050] The present application provides three embodiments of the method for manufacturing the battery cover assembly as follows:

[0051] Example 1

[0052] This embodiment is for a 280Ah frequency modulation energy storage lithium-ion battery, the rated charge and discharge current of which is 280A, and the process is as follows:

[0053] First, we started the short circuit and overcharge thermal runaway simulation test on the 280Ah frequency modulation energy storage lithium-ion battery. Before the battery test, the battery state of charge (SOC) was charged to 100%. The charging method was: first charge to 3.65V at a constant current of 1C (280A), and then charge at a constant voltage of 3.65V until the current drops to 28A. Short circuit and overcharge are the most common triggers of thermal runaway in actual operation of batteries. Therefore, the battery was short-circuited and overcharged. The test diagram is shown in the figure. Figure 4 During the battery short-circuit test, the resistance of the external circuit is less than 1 milliohm. During the short-circuit test, the internal and external temperatures of the battery cover 1, the negative pole, and the positive pole are tested to determine the minimum tolerance temperature of the battery material during short circuit. During the battery overcharge test, the battery is charged at a rated charging current of 280A until the battery opens and produces gas. During the battery puncture test, a steel needle with a diameter of 8mm is used to pierce the battery from a direction perpendicular to the battery plate, and the steel needle remains in the battery. In the battery short-circuit, overcharge and puncture tests, determine the maximum temperature that each component of the battery cover assembly needs to withstand when the battery is in thermal runaway.

[0054] By analyzing the temperature of each component of the battery cover assembly, including the temperature of the positive pole, the negative pole, the upper positive plastic part 91, the upper negative plastic part 4, the plastic plate 6, and the insulation seal, it can be found that when the battery is short-circuited, the temperature of the battery pole reaches above 500°C, and the highest temperature parts are the upper positive plastic part 91 and the upper negative plastic part 4. Therefore, it is determined that the thermal runaway insulation weak points are the upper positive plastic part 91 and the upper negative plastic part 4.

[0055] Design insulation damage prevention materials and battery cover components based on key heat resistance parameters, as follows:

[0056] A battery cover assembly comprises a cover 1, a negative upper column, a negative lower column, a positive upper column, a positive lower column 93, a first column hole 11, an upper negative plastic part 4, an upper positive plastic part 91, a plastic plate 6, an insulating seal 7, a first high-temperature insulating component and a second high-temperature insulating component, and an explosion-proof valve. The connection relationship of the above-mentioned components of the battery cover assembly is specifically shown in the above-mentioned related content, which will not be repeated here. The upper positive plastic part 91 and the upper negative plastic part 4 of the battery cover 1 are made of polyphenylene sulfide (PPS) material. The insulating seal 7 of the battery cover 1 is made of fluorosilicone rubber material. The first high-temperature insulating part 5 adopts a cylindrical structure and adopts a non-expanding high-temperature insulating material. The second high-temperature insulating part 8 adopts an annular structure, the inner ring of the annular structure adopts a non-expanding high-temperature insulating material, and the outer ring adopts an expanding high-temperature insulating material. Under heating conditions, the inner ring plays a supporting role, and the expanding high-temperature insulating material of the outer ring expands and fills the gap, which has a good insulating effect. The second high temperature insulating member 8 is composed of a mixture of 60% non-expandable high temperature insulating material and 40% expandable high temperature insulating material. The non-expandable high temperature insulating material is composed of 100% alumina material. The outer ring material is composed of 80% expandable base material, 10% foaming aid, 5% foaming catalyst, and 5% thickener. The expandable base material is phenolic resin, the foaming aid is dicyandiamide, the foaming catalyst is high-polymerization ammonium polyphosphate, and the thickener is fumed silica. The diameter of the first high temperature insulating member 5 with a cylindrical structure is 4mm and the thickness is 2mm; the outer ring diameter of the second high temperature insulating member 8 with an annular structure is 32mm, the inner ring diameter is 27mm, and the thickness is 0.8mm.

[0057] Example 2

[0058] This embodiment is for a 314Ah peak-loaded energy storage lithium-ion battery, the rated charge and discharge current of which is 157A, and the process is as follows:

[0059] First, we started the short circuit and overcharge thermal runaway simulation test on the 314Ah peak-shaving lithium-ion energy storage battery. Before the battery test, the battery state of charge (SOC) was charged to 100%. The charging method was: first charge to 3.65V at a constant current of 0.5C (157A), and then charge at a constant voltage of 3.65V until the current dropped to 15.7A. Short circuit and overcharge are the most common triggers of thermal runaway in actual operation of batteries. Therefore, the battery was short-circuited and overcharged. The test diagram is shown in the figure. Figure 4During the battery short-circuit test, the resistance of the external circuit is less than 1 milliohm. During the short-circuit test, the internal and external temperatures of the battery cover 1, the negative pole, and the positive pole are tested to determine the minimum tolerance temperature of the battery material during short circuit. During the battery overcharge test, the battery is charged at a rated charging current of 157A until the battery opens and produces gas. During the battery puncture test, a steel needle with a diameter of 8mm is used to pierce the battery from a direction perpendicular to the battery plate, and the steel needle remains in the battery. In the battery short-circuit, overcharge and puncture tests, determine the maximum temperature that each component of the battery cover assembly needs to withstand when the battery is in thermal runaway.

[0060] By analyzing the temperature of each component of the battery cover assembly, including the positive pole, negative pole, upper positive plastic part 91, upper negative plastic part 4, plastic plate 6, and insulation seal, it can be found that when the battery is short-circuited, the temperature of the battery pole reaches above 400°C, and the part with the highest temperature is the upper negative plastic part 4. Therefore, it is determined that the weak point of thermal runaway insulation is the upper negative plastic part 4.

[0061] Design insulation damage prevention materials and battery cover components based on key heat resistance parameters, as follows:

[0062] A battery cover assembly comprises a cover 1, a negative upper column, a negative lower column, a positive upper column, a positive lower column 93, a first column hole 11, an upper negative plastic part 4, an upper positive plastic part 91, a plastic plate 6, an insulating seal 7, a first high-temperature insulating component and a second high-temperature insulating component, and an explosion-proof valve. The connection relationship of the above-mentioned components of the battery cover assembly is specifically shown in the above-mentioned related content, which will not be repeated here. The upper positive plastic part 91 and the upper negative plastic part 4 of the battery cover 1 are made of polyaryletherketone (PAEK) material. The insulating seal 7 of the battery cover 1 is made of silicone rubber material. The first high-temperature insulating part 5 adopts a cylindrical structure and adopts a non-expanding high-temperature insulating material. The second high-temperature insulating part 8 adopts an annular structure, the inner ring of the annular structure adopts a non-expanding high-temperature insulating material, and the outer ring adopts an expanding high-temperature insulating material. Under heating conditions, the inner ring plays a supporting role, and the expanding high-temperature insulating material of the outer ring expands and fills the gap, which has a good insulating effect. The second high temperature insulating member 8 is composed of a mixture of 60% non-expanding high temperature insulating material and 40% expanding high temperature insulating material. The non-expanding high temperature insulating material is zirconium oxide material. The outer ring material is composed of 65% expanding base material, 20% foaming aid, 8% foaming catalyst, and 7% thickener. The expanding base material is tri-pentaerythritol, the foaming aid is polyamide, the foaming catalyst is high-polymerization ammonium polyphosphate, and the thickener is silicone gel. The diameter of the first high temperature insulating member 5 with a cylindrical structure is 4mm and the thickness is 2mm; the outer ring diameter of the second high temperature insulating member 8 with an annular structure is 32mm, the inner ring diameter is 27mm, and the thickness is 0.8mm.

[0063] Example 3

[0064] This embodiment is for a 314Ah peak-loaded energy storage lithium-ion battery, the rated charge and discharge current of which is 157A, and the process is as follows:

[0065] First, we started the short circuit and overcharge thermal runaway simulation test on the 314Ah peak-shaving lithium-ion energy storage battery. Before the battery test, the battery state of charge (SOC) was charged to 100%. The charging method was: first charge to 3.65V at a constant current of 0.5C (157A), and then charge at a constant voltage of 3.65V until the current dropped to 15.7A. Short circuit and overcharge are the most common triggers of thermal runaway in actual operation of batteries. Therefore, the battery was short-circuited and overcharged. The test diagram is shown in the figure. Figure 4 During the battery short-circuit test, the resistance of the external circuit is less than 1 milliohm. During the short-circuit test, the internal and external temperatures of the battery cover 1, the negative pole, and the positive pole are tested to determine the minimum tolerance temperature of the battery material during short circuit. During the battery overcharge test, the battery is charged at a rated charging current of 157A until the battery opens and produces gas. During the battery puncture test, a steel needle with a diameter of 8mm is used to pierce the battery from a direction perpendicular to the battery plate, and the steel needle remains in the battery. In the battery short-circuit, overcharge and puncture tests, determine the maximum temperature that each component of the battery cover assembly needs to withstand when the battery is in thermal runaway.

[0066] By analyzing the temperature of each component of the battery cover assembly, including the positive pole, negative pole, upper positive plastic part 91, upper negative plastic part 4, plastic plate 6, and insulation seal, it can be found that when the battery is short-circuited, the temperature of the battery pole reaches above 400°C, and the part with the highest temperature is the upper negative plastic part 4. Therefore, it is determined that the weak point of thermal runaway insulation is the upper negative plastic part 4.

[0067] Design insulation damage prevention materials and battery cover components based on key heat resistance parameters, as follows:

[0068] A battery cover assembly comprises a cover 1, a negative upper column, a negative lower column, a positive upper column, a positive lower column 93, a first column hole 11, an upper negative plastic part 4, an upper positive plastic part 91, a plastic plate 6, an insulating seal 7, a first high-temperature insulating component and a second high-temperature insulating component, and an explosion-proof valve. The connection relationship of the above-mentioned components of the battery cover assembly is specifically shown in the above-mentioned related content, which will not be repeated here. The upper positive plastic part 91 and the upper negative plastic part 4 of the battery cover 1 are made of polyaryletherketone (PAEK) material. The insulating seal 7 of the battery cover 1 is made of silicone rubber material. The first high-temperature insulating part 5 adopts a cylindrical structure and adopts a non-expansion type high-temperature insulating material. The second high-temperature insulating part 8 adopts an annular structure, and the inner ring and the outer ring of the annular structure are both made of non-expansion type high-temperature insulating material. The non-expansion type high-temperature insulating material is a silicon oxide material. The thickness of the cover 1 is 2 mm thicker than the thickness of the cover 1 in Example 1 and Example 2. The outer ring material is composed of 65% expansion base material, 20% foaming aid, 8% foaming catalyst, and 7% thickener. The expansion base material is tri-pentaerythritol, the foaming aid is polyamide, the foaming catalyst is high-polymerization ammonium polyphosphate, and the thickener is silicone gel. The first high-temperature insulating member 5 of the cylindrical structure has a diameter of 4mm and a thickness of 2mm; the second high-temperature insulating member 8 of the annular structure has an outer ring diameter of 32mm, an inner ring diameter of 27mm, and a thickness of 0.8mm.

[0069] Comparative Example 1

[0070] A 280Ah frequency modulation battery was made by using a battery cover assembly in the related art for experimentation, that is, the first high-temperature insulating member 5 and the second high-temperature insulating member 8 were not provided in the battery cover assembly.

[0071] Comparative Example 2

[0072] A 280Ah frequency modulation battery was made by using a battery cover assembly without the first high-temperature insulating member 5 for experiment.

[0073] Comparative Example 3

[0074] A 280Ah frequency modulation battery was made by using a battery cover assembly without the second high-temperature insulating member 8 for experiment.

[0075] Comparative Example 4

[0076] The second high-temperature insulating component 8 in the battery cover assembly was replaced with the first high-temperature insulating component 5 to make a 280Ah frequency modulation battery for experiment.

[0077] Comparative Example 5

[0078] The first high-temperature insulating component 5 in the battery cover assembly was replaced with the second high-temperature insulating component 8 to make a 280Ah frequency modulation battery for experiment.

[0079] Comparative Example 6

[0080] The battery cover assembly used was made into a 280Ah frequency modulation battery for experiment. The thickness of the first high-temperature insulating member 5 was 0.2 mm, and the thickness of the second high-temperature insulating member 8 was 0.2 mm.

[0081] The comparative experiment is as follows:

[0082] The cover plate 1 made in Examples 1 to 3 and Comparative Example n is made into a 280Ah energy storage lithium iron phosphate battery. The battery is made into a battery module with 48 strings. The lithium iron phosphate module to be tested is charged to 100% SOC. Then the thermal runaway reaction of the lithium iron phosphate battery cell is triggered by overcharging. When overcharged, charge at a constant current until the voltage reaches a point where any battery in the module has thermal runaway. The evaluation criteria for battery thermal runaway refer to GB / T36276-2018, specifically: a) the test object produces a voltage drop; b) the temperature at the monitoring point reaches the protection temperature of the battery; c) the temperature rise rate at the monitoring point is greater than or equal to 1°C / s; d) when a) + c) or b) + c) occurs, it is determined that the battery cell has thermal runaway. Observe whether the battery cell short-circuit spark occurs in the battery module, and whether the module ignites fire and explodes.

[0083] The battery modules of Examples 1 to 3 and Comparative Examples 1 to 6 were tested, and the test results are as follows:

[0084]

[0085] It can be seen from the comparative examples that the battery module without the battery cover assembly to prevent battery short circuit is prone to ignition and fire. The use of the battery cover assembly to prevent battery short circuit is conducive to preventing the battery module from catching fire. In addition, the battery cover assembly combining non-expandable high-temperature insulating material and expandable high-temperature insulating material is conducive to improving the energy density of the battery.

[0086] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0087] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery cover assembly, characterized in that: include: A cover plate (1), wherein a groove is formed on the cover plate (1), and a first pole hole (11) is formed at the bottom of the groove; A negative pole, comprising a negative lower pole (2) and a negative upper pole (3) connected to each other, part of the negative lower pole (2) being inserted into the first pole hole (11), and at least part of the negative upper pole (3) being located in the groove; An upper negative electrode plastic part (4), wherein an upper negative electrode plastic part (4) is provided between the negative electrode upper pole (3) and the groove to insulate the negative electrode upper pole (3) from the cover plate (1); A first high-temperature insulating component (5) is embedded in the negative electrode upper pole (3), the upper negative electrode plastic component (4) and the cover plate (1); the first high-temperature insulating component (5) is used to support the negative electrode upper pole (3) and the upper negative electrode plastic component (4) to prevent the negative electrode upper pole (3) from contacting the cover plate (1) after the upper negative electrode plastic component (4) is deformed by heat; the first high-temperature insulating component (5) is made of non-expansion type high-temperature insulating material.

2. The battery cover assembly according to claim 1, characterized in that: The first high-temperature insulating member (5) is in a columnar structure or an annular structure, and the non-expanding high-temperature insulating material includes at least one of silicate glass, silicate ceramics, mica, silicate cement, aluminum oxide, zirconium oxide, zinc oxide, silicon nitride, boron carbide, titanium oxide, silicon carbide, boron carbide, cerium carbide, molybdenum carbide, niobium carbide, zirconium carbide, titanium carbide, vanadium carbide, tungsten carbide, tantalum carbide, silicon nitride, boron nitride, aluminum nitride, titanium diboride, and zirconium diboride.

3. The battery cover assembly according to claim 1, characterized in that: The battery cover assembly further comprises a plastic plate (6) and an insulating sealing ring (7); the plastic plate (6) is stacked and distributed with the cover plate (1) and connected to the side of the cover plate (1) facing away from the negative upper pole (3); a second pole hole (61) is formed on the plastic plate (6); the negative lower pole (2) is plugged into the second pole hole (61); and the insulating sealing ring (7) is provided between the inner wall of the first pole hole (11) and the inner wall of the second pole hole (61) and the negative lower pole (2).

4. The battery cover assembly according to claim 3, characterized in that: The negative electrode lower column comprises a large end and a small end, the small end passes through the second electrode hole (61) and the first electrode hole (11) and is connected to the negative electrode upper column (3), and the large end abuts against the plastic plate (6); A second high-temperature insulating member (8) is disposed on the periphery of the insulating sealing ring (7); the second high-temperature insulating member (8) is ring-shaped or column-shaped; the second high-temperature insulating member (8) is located between the inner wall of the second pole hole (61) and the insulating sealing ring (7).

5. The battery cover assembly according to claim 4, characterized in that: The inner ring of the second high-temperature insulating member (8) in contact with the insulating seal ring (7) is made of non-expandable high-temperature insulating material, and the outer ring of the second high-temperature insulating member (8) in contact with the inner wall of the second pole hole (61) is made of expandable high-temperature insulating material.

6. The battery cover assembly according to claim 5, characterized in that: The intumescent high-temperature insulating material comprises an intumescent base material, a foaming aid, a foaming catalyst and a thickener.

7. The battery cover assembly according to claim 6, characterized in that: The expansion base material is phenolic resin or pentaerythritol; And / or, the foaming aid is dicyandiamide or polyamide; And / or, the foaming catalyst is high-polymerization degree ammonium polyphosphate; And / or, the thickener is fumed silica or silicone gel.

8. The battery cover assembly according to claim 1, characterized in that: The battery cover assembly also includes a positive pole and an upper positive pole plastic part (91), the positive pole includes a positive upper pole (92) and a positive lower pole (93) connected to each other, two grooves are provided on the cover (1), one of the grooves is provided with the positive upper pole (92), and the other groove is provided with the negative upper pole (3), the positive lower pole (93) passes through the bottom of the groove and is connected to the positive upper pole (92), and the upper positive pole plastic part (91) is provided between the positive upper pole (92) and the groove.

9. The battery cover assembly according to claim 8, characterized in that: The upper positive electrode plastic part (91) and the upper negative electrode plastic part (4) are made of polyphenylene sulfide material.

10. A method for manufacturing a battery cover assembly, characterized in that: include: Conducting a simulation experiment on the battery to obtain the maximum tolerance temperature of multiple components of the battery cover assembly when the battery is in thermal runaway, wherein the temperature of the upper negative electrode plastic part (4) is higher than the temperature of other components when the battery is in thermal runaway; A first high-temperature insulating component is arranged on the negative pole, and the first high-temperature insulating component is embedded in the negative upper pole (3), the upper negative plastic part (4) and the cover plate (1), and the first high-temperature insulating part (5) is used to support the negative upper pole (3) and the upper negative plastic part (4) to prevent the negative upper pole (3) from contacting the cover plate (1) after the upper negative plastic part (4) is deformed by heat; Design insulation damage prevention materials and battery cover components based on key heat resistance parameters.

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