Battery assembly and power utilization system

Abstract

The invention provides a battery assembly and a power utilization system. The battery assembly comprises a battery cell and a heat absorption part, the battery cell comprises an anti-explosion valve; the side plate is opposite to the anti-explosion valve, the heat absorption part is opposite to the anti-explosion valve and used for generating non-combustible gas, and the volume of the gas generated by the heat absorption part is larger than or equal to three times of the effective air volume of the battery cell; the heat absorption part is arranged at the position opposite to the anti-explosion valve, when the battery cell is in thermal runaway and the valve is opened, high-temperature and high-pressure gas impacts the heat absorption part, the volume of gas generated by heat absorption of the heat absorption part and the volume of gas generated by the heat absorption part are larger than the effective volume of the battery cell, combustion reaction of the runaway battery cell and the adjacent battery cell is avoided, and the damage degree of thermal runaway to the battery assembly is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery assembly and a power system. Background Art

[0002] There are multiple cells in the battery assembly. During the thermal runaway process, the explosion-proof valve will open and a large amount of flames and high-temperature substances will erupt, causing great damage to the inside of the battery cell and easily causing further risks such as short circuit and arcing. At the same time, the erupted flames can easily burn through the sealing cover, posing a greater safety hazard. Usually, in order to prevent the high-temperature and high-pressure gas from burning through the sealing cover when the explosion-proof valve of the battery cell is opened, thicker steel plates are used, and the battery assembly is insulated to prevent the high-temperature substances in the runaway process from causing arcing and short circuit risks to the battery assembly. However, the high-temperature and high-pressure gas after the explosion-proof valve is opened can easily cause a combustion reaction in the battery cell. Summary of the invention

[0003] The present application provides a battery assembly and a power system, which are at least used to solve the problem of battery thermal runaway.

[0004] In a first aspect, the present application provides a battery assembly, the battery assembly comprising a battery cell and a heat sink; the battery cell comprises an explosion-proof valve; the heat sink is opposite to the explosion-proof valve, the heat sink is used to generate non-combustible gas, and the volume of gas generated by the heat sink is greater than or equal to three times the effective air volume of the battery cell.

[0005] In a possible implementation manner, the volume of gas generated by the heat absorption element is less than or equal to eleven times the effective air volume of the battery core.

[0006] In a possible implementation, the ratio of the volume of the battery assembly to the number of the battery cells is recorded as a first value, the volume of the battery cells is recorded as a second value, and the effective air volume of the battery cells is: the difference between the first value and the second value.

[0007] In a possible implementation, the heat absorbing element includes a heat absorbing portion, the heat absorbing portion is made of a heat absorbing material, and the heat absorbing material includes a gel-state phase-changing material or a solid-state phase-changing material.

[0008] In a possible implementation, a first orthographic projection area of ​​the heat absorbing element on a plane perpendicular to the arrangement direction of the heat absorbing element and the explosion-proof valve is S1, a second orthographic projection area of ​​the explosion-proof valve on a plane perpendicular to the arrangement direction of the heat absorbing element and the explosion-proof valve is S2, and the first orthographic projection area S1 and the second orthographic projection area S2 satisfy: 0.5S2≤S1≤2.5S2.

[0009] In a possible implementation manner, along the arrangement direction of the heat absorption element and the explosion-proof valve, a distance between the heat absorption element and the explosion-proof valve is greater than or equal to 0.5 cm and less than or equal to 10 cm.

[0010] In a possible implementation, the heat absorbing element includes a heat absorbing portion and an insulating layer, and the insulating layer is coated on an outer peripheral surface of the heat absorbing portion.

[0011] In a possible implementation, an angle is formed between a line connecting a center point of the explosion-proof valve and a center point of the heat absorption component and a straight line perpendicular to a surface of the explosion-proof valve of the battery cell, and the angle is less than 10 degrees.

[0012] In a possible implementation manner, there are multiple battery cells, and each battery cell corresponds to one heat absorption component.

[0013] By arranging a heat absorber at a position opposite to the explosion-proof valve, when the battery cell opens the valve due to thermal runaway, high-temperature and high-pressure gas impacts the heat absorber, and the heat absorber absorbs heat to produce non-combustible gas. The volume of gas produced by the heat absorber is greater than or equal to three times the effective air volume of the battery cell, thereby avoiding combustion reactions between the runaway battery cell and adjacent battery cells, thereby reducing the degree of damage to the battery components caused by thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments are briefly introduced below.

[0015] Figure 1 It is a schematic diagram of a three-dimensional structure of a battery assembly provided by an embodiment of the present application from one viewing angle;

[0016] Figure 2 is a schematic diagram of a three-dimensional structure of a battery assembly provided by an embodiment of the present application from another perspective;

[0017] Figure 3 It is a schematic diagram of the three-dimensional structure of a heat absorption component provided in one embodiment of the present application.

[0018] Description of reference numerals:

[0019] Battery assembly-100, battery cell-10, explosion-proof valve-11, side plate-20, heat absorption component-30, heat absorption part-31, insulation layer-32. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] The following descriptions of the various embodiments are made with reference to the attached drawings to illustrate specific embodiments that may be implemented in the present application. Directional terms mentioned herein, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are intended to better and more clearly describe and understand the present application, rather than to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0022] In addition, the serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0023] The present application provides an electricity consumption system, and the electricity consumption system includes the battery assembly 100 provided in the present application.

[0024] See also Figure 1 and Figure 2 The battery assembly 100 includes a battery cell 10, a side plate 20 and a heat absorber 30; the battery cell 10 includes an explosion-proof valve 11; the side plate 20 is opposite to the explosion-proof valve 11; the heat absorber 30 is arranged on the side plate 20, the heat absorber 30 is opposite to the explosion-proof valve 11, and the heat absorber 30 is used to generate non-combustible gas, and the gas volume generated by the heat absorber 30 is greater than or equal to three times the effective air volume of the battery cell 10.

[0025] By arranging the heat absorbing member 30 at a position opposite to the explosion-proof valve 11 on the side plate 20, when the battery cell 10 opens the valve due to thermal runaway, the high-temperature and high-pressure gas impacts the heat absorbing member 30, and the heat absorbing member 30 absorbs heat to generate non-combustible gas. The volume of the gas generated by the heat absorbing member 30 is greater than or equal to three times the effective air volume of the battery cell 10. Therefore, the gas generated by the heat absorbing member 30 can prevent the runaway battery cell 10 and the adjacent battery cells 10 from having a combustion reaction, thereby reducing the degree of damage to the battery assembly 100 caused by thermal runaway.

[0026] Specifically, after a battery cell 10 has thermal runaway, it will affect at least two battery cells 10 adjacent to the battery cell 10. In order to effectively reduce the thermal runaway problem, the gas volume generated by the heat absorber 30 is set to be greater than or equal to three times the effective air volume of the battery cell 10, that is, the gas volume generated by one heat absorber 30 occupies at least the sum of the effective air volumes of the three battery cells 10, and the air volume that can be discharged by the gas generated by one heat absorber 30 is at least the sum of the effective air volumes of the three battery cells 10, ensuring that the gas generated by the heat absorber 30 can effectively discharge the air near the corresponding battery cell 10 and the two battery cells 10 adjacent to the battery cell 10, thereby avoiding a combustion reaction between the runaway battery cell 10 and the adjacent battery cells 10.

[0027] The ratio of the volume of the battery assembly 100 to the number of the battery cells 10 is recorded as a first value, the volume of the battery cells 10 is recorded as a second value, and the effective air volume of the battery cells 10 is: the difference between the first value and the second value.

[0028] The volume of the battery assembly 100 is V pack , the volume of a battery cell 10 is V cell , the number of cells 10 in the battery assembly 100 is z, and the effective air volume around a cell 10 in the battery assembly 100 is V cell_气 , then the effective air volume of the battery cell 10 is: V cell_气 =V pack / zV cell , where V pack / z is the first value, V cell is the second value.

[0029] The volume of a battery cell 10 is the apparent volume of the battery cell 10 , which can be calculated based on the size of the battery cell 10 ; the volume of the battery assembly 100 can be calculated based on the apparent size of the battery assembly 100 .

[0030] The heat absorbing member 30 may be disposed on the side plate 20 directly facing the explosion-proof valve 11 , so that the heat absorbing member 30 can absorb heat more quickly, thereby reducing the impact on other battery cells 10 .

[0031] The heat absorbing element 30 is a material that can absorb heat at high temperatures and generate gas, thereby absorbing the heat of the runaway battery cell 10 during thermal runaway. The generated gas can discharge the air near the runaway battery cell 10 out of the battery assembly 100, reducing the proportion of air in the battery assembly 100.

[0032] Optionally, the heat absorption element 30 is a sheet-like high heat absorption material that can absorb heat and release non-combustible gases (such as CO2 or water vapor, etc.) in the temperature range of 100-250°C to suppress the combustion reaction of the runaway battery cell 10 and the adjacent battery cell 10, thereby reducing the degree of damage to the battery assembly 100 caused by thermal runaway.

[0033] See also Figure 3 For example, the heat absorbing member 30 includes a heat absorbing portion 31, which is made of a heat absorbing material, and the heat absorbing material includes a gel-state phase-changing material or a solid-state phase-changing material. For example, the heat absorbing material is any one of solid hydrogel, NaHCO3, Na2CO3, Ca(HCO3)2, and hydrated salt. The heat absorbing portion 31 is made of a solid material.

[0034] The heat absorption part 31 absorbs the heat during the thermal runaway of the battery cell 10 . The heat absorption part 31 generates a large amount of non-flammable gas under the action of the heat, discharges the effective air around the battery cell 10 out of the battery assembly 100 , and reduces the air ratio in the battery assembly 100 .

[0035] For example, the heat absorbing member 30 further includes an insulating layer 32, and the insulating layer 32 is coated on the outer circumference of the heat absorbing portion 31. The insulating layer 32 completely wraps around the outer circumference of the heat absorbing portion 31 to seal the heat absorbing portion 31. When the heat absorbing portion 31 absorbs heat and generates gas, the gas generated by the heat absorbing portion 31 increases the overall volume of the heat absorbing member 30, thereby squeezing the effective air around the battery cell 10 and discharging it to the outside of the battery assembly 100.

[0036] Optionally, the insulating layer 32 is made of a sealing material, and the sealing material may be a plastic film, an aluminum-plastic film or other sealing films, wherein the plastic film may be a polypropylene film (PP), a polyethylene glycol terephthalate film (PET), or a polyimide film (PI).

[0037] For example, the volume of gas generated by the heat sink 30 is less than or equal to eleven times the effective air volume in the battery core 10 .

[0038] Furthermore, after a thermal runaway occurs, a battery cell 10 may affect a maximum of ten battery cells 10 adjacent to the battery cell 10. In order to further reduce the thermal runaway problem, the gas volume generated by the heat absorber 30 is set to be less than or equal to eleven times the effective air volume of the battery cell 10, that is, the gas volume generated by one heat absorber 30 can occupy a maximum of the sum of the effective air volumes of the eleven battery cells 10, and the maximum air volume that can be discharged by the gas generated by one heat absorber 30 is the sum of the effective air volumes of the eleven battery cells 10, which ensures that the air volume around the corresponding thermal runaway battery cell 10 can be discharged, thereby reducing the volume and mass of the excess heat absorber 30 material occupied in the battery assembly 100, so as to reduce the impact of the heat absorber 30 on the energy density of the battery assembly 100.

[0039] For example, a battery cell 10 may affect up to ten battery cells 10 adjacent to the battery cell 10 after thermal runaway occurs, which means that multiple battery cells 10 are arranged along the first direction, wherein a battery cell 10 at a certain position may affect five battery cells 10 adjacent to the battery cell 10 at both ends along the first direction after thermal runaway occurs. Or for example, a battery cell 10 may affect up to ten battery cells 10 adjacent to the battery cell 10 after thermal runaway occurs, which means that multiple battery cells 10 are arranged along the first direction to form a battery cell group, and multiple battery cell groups are arranged along the second direction, wherein a battery cell 10 at a certain position may affect ten battery cells 10 along the first direction and / or the second direction centered on the battery cell 10 after thermal runaway occurs.

[0040] For example, a first orthographic projection area of ​​the heat absorber 30 on a plane perpendicular to the arrangement direction of the heat absorber 30 and the explosion-proof valve 11 is S1, and a second orthographic projection area of ​​the explosion-proof valve 11 on a plane perpendicular to the arrangement direction of the heat absorber 30 and the explosion-proof valve 11 is S2. The first orthographic projection area S1 and the second orthographic projection area S2 satisfy: 0.5S2≤S1≤2.5S2.

[0041] The heat absorbing member 30 is opposite to and spaced from the explosion-proof valve 11 . The first orthographic projection area S1 of the heat absorbing member 30 is the area of ​​the heat absorbing member 30 , and the second orthographic projection area S2 of the explosion-proof valve 11 is the area of ​​the explosion-proof valve 11 .

[0042] The first orthographic projection area S1 can be 0.5S2, 0.6S2, 0.9S2, 1.1S2, 1.3S2, 1.5S2, 1.8S2, 2.0S2, 2.3S2 or 2.5S2, and the first orthographic projection area S1 and the second orthographic projection area S2 can satisfy: 0.5S2≤S1≤2.5S2. If the first orthographic projection area S1 is less than 0.5S2, it is easy to cause the heat absorption efficiency of the heat absorption element 30 to be too slow during the thermal runaway process; if the first orthographic projection area S1 is greater than 2.5S2, it is easy to cause low heat absorption efficiency.

[0043] For example, along the arrangement direction of the heat absorbing element 30 and the explosion-proof valve 11 , the distance between the heat absorbing element 30 and the explosion-proof valve 11 is greater than or equal to 0.5 cm and less than or equal to 10 cm.

[0044] The distance between the heat absorbing member 30 and the explosion-proof valve 11 may be the distance between the center points on the opposing surfaces of the two, or may be the average distance between the corresponding points on the two opposing surfaces of the two.

[0045] The distance between the heat absorbing element 30 and the explosion-proof valve 11 can be 0.5 cm, 1.2 cm, 2.5 cm, 3.0 cm, 5 cm, 6 cm, 8 cm, 9 cm or 10 cm. The distance in the range of 0.5 cm-10 cm can effectively improve the utilization rate of the heat absorbing element 30. If the distance is too small, the air pressure at the battery cell 10 will be too high during thermal runaway, which will cause a greater impact on the heat absorbing element 30 and affect the utilization rate of the heat absorbing element 30. If the distance is too large, the heat absorption rate of the material will be reduced.

[0046] For example, the surface of the heat absorbing member 30 facing the explosion-proof valve 11 is parallel to the surface of the explosion-proof valve 11 facing the heat absorbing member 30 .

[0047] When the surface of the heat absorbing member 30 facing the explosion-proof valve 11 is parallel to the surface of the explosion-proof valve 11 facing the heat absorbing member 30 , the utilization rate and heat absorption rate of the heat absorbing member 30 can be effectively improved.

[0048] For example, the surface of the heat absorber 30 facing the explosion-proof valve 11 may intersect with the surface of the explosion-proof valve 11 facing the heat absorber 30 to reduce the installation accuracy of the heat absorber 30. When the surface of the heat absorber 30 facing the explosion-proof valve 11 intersects with the surface of the explosion-proof valve 11 facing the heat absorber 30, the distance between one end of the surface of the heat absorber 30 facing the explosion-proof valve 11 and one end of the surface of the explosion-proof valve 11 facing the heat absorber 30 becomes smaller, and the other distances become larger. The distance between the center points of the two or the average distance between the two can be within the range of 0.5cm-10cm.

[0049] For example, there is an angle between a line connecting the center point of the explosion-proof valve 11 and the center point of the heat absorption element 30 and a straight line perpendicular to the surface of the explosion-proof valve 11 of the battery cell 10 , and the angle is less than 10 degrees.

[0050] The angle is less than 10 degrees, which ensures that the heat absorbing element 30 and the explosion-proof valve 11 are not offset too much, and ensures that the heat absorbing element 30 can absorb the heat near the explosion-proof valve 11 in time.

[0051] In the present application, the amount of the heat absorption part 31 can be calculated according to the chemical formula in the reaction process of the heat absorption material of the heat absorption part 31, so as to control the volume of the gas generated by the heat absorption part 31 to be greater than or equal to three times the effective air volume of the battery cell 10 and less than or equal to eleven times the effective air volume of the battery cell 10.

[0052] For the heat absorbing element 30, the reaction equation of the heat absorbing material therein is as follows:

[0053] aA(s)→bB(s)+cC(g)

[0054] Among them, A is the total type of reactants, B is the total type of solid substances in the product, and C is the total type of gaseous substances in the product. a, b, and c are the stoichiometric ratios of the three types of substances, respectively.a 、M b 、M 气 The molar masses (g / mol) of three types of substances A, B, and C are respectively. After determining the type of A, its molar mass M can be obtained by theoretical calculation a , through chemical reaction balancing, obtain the stoichiometric ratio of the reaction equation.

[0055] The mass of the reactant is m a , which can be obtained by weighing, the mass of the generated gas is m 气 , the unit is g, the volume of the gas produced is V 气 , the unit is L, and the two satisfy the following relationship:

[0056] V 气 =22.4*(L / mol)*m 气 / M 气 =22.4*c*m a / (a*M a )

[0057] The present application is further described below in conjunction with the embodiments and comparative examples. It should be understood that the embodiments and comparative examples provided in the present application are only to help understand the present application and should not be regarded as specific limitations of the present application.

[0058] Embodiment 1: Twenty battery cells 10 are arranged in sequence along a preset direction, and each battery cell 10 meets the following requirements: the size of the battery cell 10 is 480*84*15mm, and the mass is 1.3kg. Thermal runaway triggering conditions: room temperature (25°C), 100% SOC, single battery cell 10 is triggered by a needle, and a heat absorber 30 is arranged on the side panel 20 facing the explosion-proof valve 11 of the battery cell 10. The heat absorbing material in the heat absorber 30 is a solid hydrogel with a water content of 90%, a mass of m, a density of 1030kg / m3, and is heat-sealed with a PET film. Among them, the specific heat capacity c2 of the hydrogel is 4200J kg -1 K -1 , the latent heat of vaporization is 1820 kJ kg -1 K -1 The volume utilization rate of the battery assembly 100 is that the effective air volume around a single battery cell 10 in the battery assembly 100 is 25% of the volume of the battery cell 10 .

[0059] Hydrogel(s)→Residue(s)+H2O(g)

[0060] The volume of water vapor generated for 1.1 g of hydrogel is V gas =1.1*0.9*22.4 / 18(L)

[0061] Among them, the hydrogel produces non-combustible gas under high temperature conditions, which can effectively remove the air near the out-of-control battery cell 10 and the adjacent battery cell 10, reduce the oxygen concentration, and inhibit the combustion or flame of the out-of-control battery cell 10 and the adjacent battery cell 10.

[0062] Embodiment 2, Embodiment 3, Embodiment 4 and Comparative Example 1, Comparative Example 2: The other steps are the same as in Embodiment 1, and the specific differences are shown in Table 1. Table 1 shows the combustion reaction results of the out-of-control battery cell 10 and the adjacent battery cells 10 after selecting different masses of heat absorption components 30 under different types and models of battery cells 10 in each embodiment and comparative example.

[0063] Table 1

[0064]

[0065]

[0066] As can be seen from Table 1, specifically, through Examples 1-4 and Comparative Examples 1-2, it can be seen that when the volume of gas generated by the heat absorbing member 30 is greater than or equal to three times the effective air volume of the battery cell 10, the combustion reaction of the runaway battery cell 10 and the adjacent battery cell 10 can be avoided. Example 1, Example 3 and Example 4 show that for different types of battery cells 10 (including ternary and iron-lithium battery cells), the use of heat absorbing members 30 of appropriate sizes can avoid the combustion reaction of the runaway battery cell 10 and the adjacent battery cell 10; Example 1 and Example 2 show that for battery cells 10 of different sizes and capacities, the use of heat absorbing members 30 of appropriate sizes can avoid the combustion reaction of the runaway battery cell 10 and the adjacent battery cell 10; Example 1 and Comparative Example 1, as well as Example 4 and Comparative Example 2 show that when the volume of gas generated by the heat absorbing member 30 is less than three times the effective air volume of the battery cell 10, the runaway battery cell 10 and the adjacent battery cell 10 are prone to combustion reactions.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the protection scope of the present application. Although the present application is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

[0068] The above are some implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A battery assembly, characterized in that: include: A battery cell, wherein the battery cell comprises an explosion-proof valve; A heat absorbing member, the heat absorbing member is opposite to the explosion-proof valve, the heat absorbing member is used to generate non-combustible gas, and the volume of gas generated by the heat absorbing member is greater than or equal to three times the effective air volume of the battery core.

2. The battery assembly according to claim 1, characterized in that: The volume of gas generated by the heat absorption element is less than or equal to eleven times the effective air volume of the battery core.

3. The battery assembly according to claim 1, characterized in that: The ratio of the volume of the battery assembly to the number of the battery cells is recorded as a first value, the volume of the battery cells is recorded as a second value, and the effective air volume of the battery cells is: the difference between the first value and the second value.

4. The battery assembly according to claim 1, characterized in that: The heat absorbing element comprises a heat absorbing portion, the heat absorbing portion is made of a heat absorbing material, and the heat absorbing material comprises a gel phase-changing material or a solid phase-changing material.

5. The battery assembly according to claim 1, characterized in that: A first orthographic projection area of ​​the heat absorbing element on a plane perpendicular to the arrangement direction of the heat absorbing element and the explosion-proof valve is S1, and a second orthographic projection area of ​​the explosion-proof valve on a plane perpendicular to the arrangement direction of the heat absorbing element and the explosion-proof valve is S2. The first orthographic projection area S1 and the second orthographic projection area S2 satisfy: 0.5S2≤S1≤2.5S2.

6. The battery assembly according to claim 1, characterized in that: Along the arrangement direction of the heat absorbing element and the explosion-proof valve, the distance between the heat absorbing element and the explosion-proof valve is greater than or equal to 0.5 cm and less than or equal to 10 cm.

7. The battery assembly according to claim 1, characterized in that: The heat absorbing member includes a heat absorbing portion and an insulating layer, wherein the insulating layer covers an outer peripheral surface of the heat absorbing portion.

8. The battery assembly according to claim 1, characterized in that: An angle is formed between a line connecting the center point of the explosion-proof valve and the center point of the heat absorption component and a straight line perpendicular to the surface of the explosion-proof valve of the battery cell, and the angle is less than 10 degrees.

9. The battery assembly according to claim 1, characterized in that: There are multiple battery cells, and each battery cell corresponds to one heat absorption component.

10. An electricity system, characterized in that: Comprising a battery assembly as described in any one of claims 1 to 9.

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