Flame-retardant heat-absorbing lithium battery

Abstract

The utility model provides a kind of flame-retardant heat-absorbing lithium battery, including battery shell, at least one group of positive and negative pole module and at least one flame-retardant heat-absorbing pole piece are arranged in battery shell, flame-retardant heat-absorbing pole piece includes fragile shell, fragile shell is filled with flame-retardant heat-absorbing material, the outside of fragile shell and positive and negative pole module are pasted, battery shell is filled with electrolyte, positive and negative pole module and flame-retardant heat-absorbing pole piece are placed in electrolyte.Battery inside is added by "flame-retardant heat-absorbing pole piece", supplement efficient flame-retardant heat-absorbing material, in the initial stage of battery uncontrolled heat release, release flame-retardant heat-absorbing material in time by fragile shell rupture, interfere, destroy combustion process, control the rise of heat, greatly reduce the risk of combustion caused by battery thermal runaway.Flame-retardant heat-absorbing pole piece is a pole piece that is separately added, does not directly affect original positive, negative, diaphragm, but inserts a pole piece, the influence generated is indirect, relatively small.

Description

Technical Field

[0001] This utility model belongs to the field of battery technology and relates to a battery cell, particularly a flame-retardant heat-absorbing lithium battery. Background Technology

[0002] Currently, lithium-ion battery cells are generally integrated into a cell using processing methods such as stacking, winding, and lamination of the positive electrode, negative electrode, and separator. The stacking process involves cutting the cathode, anode, and separator into small pieces, stacking them, pressing them together to form small battery cells, and then stacking and connecting these small cells in parallel to form a large battery cell. The winding process involves rolling the positive electrode, negative electrode, and separator together to form a lithium-ion battery cell.

[0003] The main components of a lithium-ion battery are: positive electrode, negative electrode, separator, and electrolyte. The electrodes, separator, and electrolyte solvent are all substances that can participate in combustion. However, the battery interior severely lacks flame-retardant and heat-absorbing materials. In other words, a lithium-ion battery is like a flammable and explosive powder keg; the battery is filled with flammable substances but lacks corresponding flame-retardant materials. When the battery experiences internal thermal runaway due to external impact, overcharging, or over-discharging, the internal chemical substances react, leading to difficult-to-prevent combustion accidents that are also difficult to extinguish once burning.

[0004] For example, Chinese patent document 201610118452.9 discloses a flame-retardant coating, belonging to the field of lithium-ion battery technology, comprising the following raw materials by mass percentage: 15-50% flame-retardant additive, 45-80% solvent, and 0.5-12% binder. This invention also provides a lithium-ion battery using the above-mentioned flame-retardant coating and its preparation method. This invention has flame-retardant, heat-insulating, and insulating properties, and can effectively prevent and suppress large-scale thermal runaway of lithium-ion batteries through both chemical and physical means, thereby improving the safety of lithium-ion batteries.

[0005] In the aforementioned technical solutions, coating the lithium battery cell with a flame-retardant coating to achieve flame retardancy involves attaching the flame-retardant material to the existing separator. However, this significantly reduces the conductivity of the electrolyte, thus raising questions about its practicality and feasibility. Another method for flame retardancy involves directly adding a flame-retardant, endothermic solvent to the electrolyte, which also greatly reduces the electrolyte's conductivity. Therefore, this method also faces practicality and feasibility issues. Utility Model Content

[0006] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a flame-retardant, heat-absorbing lithium battery.

[0007] The objective of this utility model can be achieved through the following technical solution: a flame-retardant heat-absorbing lithium battery, comprising a battery casing, wherein at least one set of positive and negative electrode modules and at least one flame-retardant heat-absorbing electrode are disposed inside the battery casing, wherein the flame-retardant heat-absorbing electrode includes a fragile shell, wherein the fragile shell is filled with a flame-retardant heat-absorbing material, wherein the outer side of the fragile shell is in contact with the positive and negative electrode modules, wherein the battery casing is filled with an electrolyte, and wherein the positive and negative electrode modules and the flame-retardant heat-absorbing electrode are placed in the electrolyte.

[0008] In the above-mentioned flame-retardant heat-absorbing lithium battery, a plurality of positive and negative electrode modules and at least two flame-retardant heat-absorbing electrode sheets are alternately stacked to form a cell, the plurality of positive and negative electrode modules are connected in parallel, and the cell is placed in the electrolyte in a flat state.

[0009] In the above-mentioned flame-retardant heat-absorbing lithium battery, several positive and negative electrode modules are stacked in sequence, the flame-retardant heat-absorbing electrode sheet is stacked on the top surface of several positive and negative electrode modules, the flame-retardant heat-absorbing electrode sheet is stacked on the bottom surface of several positive and negative electrode modules, and several positive and negative electrode modules are connected in parallel.

[0010] In the above-mentioned flame-retardant heat-absorbing lithium battery, the positive and negative electrode modules include a negative electrode sheet, a separator, and a positive electrode sheet stacked in sequence. The positive electrode sheet is attached to one side of the fragile shell, and the negative electrode sheet is attached to the other side of the fragile shell.

[0011] In the above-mentioned flame-retardant heat-absorbing lithium battery, at least two flame-retardant heat-absorbing electrodes are arranged on an ion-conductive separator to form a flame-retardant heat-absorbing integrated sheet. The positive and negative electrode modules are stacked with the flame-retardant heat-absorbing integrated sheet to form a battery cell. The battery cell is placed in the electrolyte in a curled state.

[0012] In the aforementioned flame-retardant heat-absorbing lithium battery, the positive and negative electrode modules include a second positive electrode, a second separator, a second negative electrode, and a third separator stacked sequentially, with the third separator attached to one side of the easily damaged casing.

[0013] In the above-mentioned flame-retardant heat-absorbing lithium battery, the flame-retardant heat-absorbing electrode is arranged longitudinally, and a plurality of longitudinal flame-retardant heat-absorbing electrodes are arranged on the ion-conducting separator, with a gap area set between adjacent flame-retardant heat-absorbing electrodes.

[0014] In the above-mentioned flame-retardant heat-absorbing lithium battery, the flame-retardant heat-absorbing electrode is arranged laterally, and at least two laterally arranged flame-retardant heat-absorbing electrodes are arranged on the ion-conducting separator, with a gap area between adjacent flame-retardant heat-absorbing electrodes.

[0015] In the aforementioned flame-retardant heat-absorbing lithium battery, the flame-retardant heat-absorbing material is specifically a flame-retardant heat-absorbing solid material or a flame-retardant heat-absorbing solvent.

[0016] Compared with existing technologies, this flame-retardant heat-absorbing lithium battery has the following advantages: 1. The battery is equipped with "flame-retardant heat-absorbing plates" to supplement the high-efficiency flame-retardant heat-absorbing material. In the early stage of uncontrolled heat release of the battery, the flame-retardant heat-absorbing material is released in time through the cracking of the fragile shell, which interferes with and destroys the combustion process, controls the rise of heat, and greatly reduces the risk of combustion caused by battery thermal runaway.

[0017] 2. The addition of "stacked flame-retardant heat-absorbing electrodes" inside the stacked battery has very little impact on the original conductivity and the increased volume is also relatively small. It is highly practical and provides a practical and effective flame-retardant method for lithium batteries.

[0018] 3. A "wound flame-retardant heat-absorbing electrode" is installed inside the wound battery. This electrode contains a large-area ion-conducting separator, ensuring that the impact on conductivity is minimized. This provides a practical and effective flame-retardant method for lithium batteries at an acceptable and feasible cost. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of Example 1 of the flame-retardant heat-absorbing lithium battery.

[0020] Figure 2 This is a schematic diagram of the structure of Example 2 of the flame-retardant heat-absorbing lithium battery.

[0021] Figure 3 This is a schematic diagram of the structure of the flame-retardant heat-absorbing electrode in Example 1 or Example 2.

[0022] Figure 4 This is a schematic diagram of the structure of Example 3 of the flame-retardant heat-absorbing lithium battery.

[0023] Figure 5 This is a schematic diagram of the structure of the flame-retardant heat-absorbing integrated sheet in Example 3.

[0024] Figure 6 This is a schematic diagram of the structure of the flame-retardant heat-absorbing integrated sheet in Example 4 of this flame-retardant heat-absorbing lithium battery.

[0025] In the diagram, 1 is the negative electrode plate 1; 2 is the separator 1; 3 is the positive electrode plate 1; 4 is the flame-retardant heat-absorbing electrode plate; 4a is the easily damaged shell; 4b is the flame-retardant heat-absorbing material; 5 is the positive electrode plate 2; 6 is the separator 2; 7 is the negative electrode plate 2; 8 is the separator 3; and 9 is the ion-conducting separator. Detailed Implementation

[0026] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0027] Example 1

[0028] like Figure 1 and3 As shown, this flame-retardant heat-absorbing lithium battery includes a battery casing. Inside the casing are at least one set of positive and negative electrode modules and at least one flame-retardant heat-absorbing electrode 4. The flame-retardant heat-absorbing electrode 4 includes a fragile shell 4a filled with a flame-retardant heat-absorbing material 4b. The outer surface of the fragile shell 4a is in contact with the positive and negative electrode modules. The battery casing is filled with electrolyte, and the positive and negative electrode modules and the flame-retardant heat-absorbing electrode 4 are placed in the electrolyte. The flame-retardant heat-absorbing electrode 4 is a separately added electrode and does not directly affect the original positive electrode, negative electrode, or separator. Instead, it is an inserted electrode, and its impact is indirect and relatively small.

[0029] Preferably, the flame-retardant heat-absorbing material 4b is a flame-retardant heat-absorbing solid material or a flame-retardant heat-absorbing solvent. The specific components of the flame-retardant heat-absorbing solid material and the flame-retardant heat-absorbing solvent are existing technologies. The flame-retardant substances include, but are not limited to, phosphorus-based flame retardants, and the heat-absorbing substances are non-flammable solvents that can absorb a large amount of heat; therefore, they will not be described in detail here. The fragile shell 4a is specially designed to easily crack and dissolve under various conditions such as mechanical impact, compression, puncture, overheating, and fire.

[0030] Preferably, a plurality of positive and negative electrode modules and at least two flame-retardant heat-absorbing electrode sheets 4 are alternately stacked to form a battery cell, and the plurality of positive and negative electrode modules are connected in parallel, with the battery cell placed in the electrolyte in a flat state.

[0031] This process is a lamination process, in which multiple sets of positive and negative electrode modules and flame-retardant heat-absorbing electrode sheets 4 are laid flat and stacked to form a lamination structure. A flame-retardant heat-absorbing electrode sheet 4 is set between each pair of adjacent positive and negative electrode modules, that is, the positive and negative electrode modules are separated by the flame-retardant heat-absorbing electrode sheet 4.

[0032] The flame-retardant heat-absorbing electrode 4 here is composed of a single piece of flame-retardant heat-absorbing material 4b, that is, it does not contain an ion-conducting membrane 9. The flame-retardant heat-absorbing electrode 4 has a simple structure and simple process, and hardly affects the original conductivity.

[0033] Alternatively, the "stacked flame-retardant heat-absorbing electrode 4" configuration may include a portion of the area of ​​an ion-conducting membrane 9.

[0034] Preferably, the positive and negative electrode module includes a negative electrode plate 1, a separator 2, and a positive electrode plate 3 stacked in sequence. The positive electrode plate 3 is attached to one side of the fragile shell 4a, and the negative electrode plate 1 is attached to the other side of the fragile shell 4a.

[0035] Example 2

[0036] The difference between this embodiment and Embodiment 1 is: like Figure 2 and 3 As shown, several positive and negative electrode modules are laid flat in sequence, flame-retardant heat-absorbing plates 4 are stacked on the top surface of several positive and negative electrode modules, flame-retardant heat-absorbing plates 4 are stacked on the bottom surface of several positive and negative electrode modules, and several positive and negative electrode modules are connected in parallel.

[0037] This process is called lamination process two. Multiple sets of positive and negative electrode modules are stacked and placed in the middle part, with flame-retardant heat-absorbing electrode sheets 4 attached to both sides. The entire cell is placed in the electrolyte in a flat state. The structure of lamination process two is similar to that of lamination process one, both adopting a flat state. The positive and negative electrode modules of lamination process two have the same composition structure as those of lamination process one.

[0038] like Figure 3 As shown, the flame-retardant heat-absorbing electrode 4 here is composed of a single piece of flame-retardant heat-absorbing material 4b. The flame-retardant heat-absorbing electrode 4 has a simple structure and simple manufacturing process, and it hardly affects the original conductivity.

[0039] The impact on the conductivity of stacked solar cells is analyzed as follows: 1. Lithium-ion exchange mainly occurs within the wafer stack; lithium-ion exchange between wafers is rare and negligible. Note: Samsung SDI discovered through isotope labeling that the amount of lithium-ion exchange between adjacent wafers is less than 0.1% of the total capacity (Adv. Energy Mater. 2021).

[0040] 2. Electronic switching must be conducted through an external parallel circuit (tab connection) and cannot be directly conducted across the laminations.

[0041] Therefore, the lithium-ion and electron exchange between the stacked cells can be ignored. Thus, adding the flame-retardant heat-absorbing electrode 4 between the stacked cells has almost zero impact on the conductivity.

[0042] Example 3

[0043] The difference between this embodiment and embodiments one and two is: like Figure 4 As shown, at least two flame-retardant heat-absorbing electrodes 4 are arranged on an ion-conducting membrane 9 to form a flame-retardant heat-absorbing integrated sheet. The positive and negative electrode modules are stacked with the flame-retardant heat-absorbing integrated sheet to form a battery cell. The battery cell is placed in the electrolyte in a curled state.

[0044] This process is a winding process, which uses only one set of relatively long positive and negative electrode modules and one relatively long flame-retardant heat-absorbing integrated sheet. After the two are bonded together, they are wound up. In the winding structure, the flame-retardant heat-absorbing integrated sheet isolates the positive and negative electrode modules between different coils.

[0045] Preferably, the positive and negative electrode module includes a positive electrode plate 2 5, a separator 2 6, a negative electrode plate 2 7, and a separator 3 8 stacked in sequence, with the separator 3 8 attached to one side of the easily damaged shell 4a.

[0046] like Figure 5 As shown, preferably, the flame-retardant heat-absorbing electrode 4 is arranged longitudinally, and a plurality of longitudinal flame-retardant heat-absorbing electrode 4 are arranged on the ion-conductive diaphragm 9, with a gap area provided between adjacent flame-retardant heat-absorbing electrode 4.

[0047] The flame-retardant heat-absorbing electrode 4 is a rectangular sheet, with its length parallel to the width of the ion-conducting membrane 9. Several flame-retardant heat-absorbing electrodes 4 are arranged along the length of the ion-conducting membrane 9. There is a certain spacing between adjacent flame-retardant heat-absorbing electrodes 4, which is part of the ion-conducting membrane 9. The ion-conducting membrane 9 provides good ion conductivity, while the spacing allows for larger conductive gaps in the flame-retardant heat-absorbing electrodes 4, thereby effectively reducing the impact on conductivity.

[0048] Example 4

[0049] The difference between this embodiment and Embodiment 3 is: like Figure 6 As shown, preferably, the flame-retardant heat-absorbing electrode 4 is arranged laterally, and at least two transverse flame-retardant heat-absorbing electrodes 4 are arranged on the ion-conducting membrane 9, with a gap area provided between adjacent flame-retardant heat-absorbing electrodes 4.

[0050] The flame-retardant heat-absorbing electrode 4 is an elongated strip, with its length parallel to the length of the ion-conducting membrane 9. At least two flame-retardant heat-absorbing electrodes 4 are arranged along the width of the ion-conducting membrane 9. There is a certain spacing between adjacent flame-retardant heat-absorbing electrodes 4, which is part of the ion-conducting membrane 9. The spacing allows for a larger conductive gap in the flame-retardant heat-absorbing electrodes 4, thereby effectively reducing the impact on conductivity.

[0051] In summary, the “wound flame-retardant heat-absorbing electrode 4” is constructed in a manner that includes at least a portion of the area of ​​an ion-conducting membrane 9.

[0052] When not subjected to mechanical impact, compression, puncture, overheating, or fire, the fragile casing 4a remains stable and its sealing performance is unaffected. However, when subjected to mechanical impact, compression, puncture, overheating, or fire, the fragile casing 4a rapidly ruptures and dissolves, releasing the internal flame-retardant heat-absorbing material 4b. This heat-absorbing material absorbs the heat generated by the reaction, while the flame-retardant material prevents the combustion material from igniting, thus improving the safety of the battery cell and reducing or even eliminating the risk of battery thermal runaway at its source.

[0053] It is evident that by installing flame-retardant heat-absorbing plates 4 inside the battery cell, internal intervention can be provided for potential thermal runaway and combustion disasters, greatly improving the success rate of eliminating thermal runaway and preventing battery cell combustion.

[0054] The specific embodiments described herein are merely illustrative examples of the spirit of this invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or substitute them with similar methods, without departing from the spirit of this invention or exceeding its defined scope. Although this invention has been detailed and described in the accompanying drawings and foregoing description, such descriptions are considered illustrative or exemplary rather than restrictive. It should be understood that changes and modifications can be made by those skilled in the art within the scope of the following claims. Specifically, this invention covers additional embodiments having any combination of features from the different embodiments described above. With regard to the use of the expressions "general" or "substantially," this patent application should be understood to disclose that the disclosure equally fully satisfies these features and values, i.e., without any of the foregoing characterizations as "general" or "substantially."

[0055] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

Claims

1. A flame-retardant heat-absorbing lithium battery, comprising a battery casing, characterized in that, The battery casing contains at least one set of positive and negative electrode modules and at least one flame-retardant heat-absorbing electrode. The flame-retardant heat-absorbing electrode includes a fragile shell, which is filled with flame-retardant heat-absorbing material. The outer surface of the fragile shell is in contact with the positive and negative electrode modules. The battery casing is filled with electrolyte, and the positive and negative electrode modules and the flame-retardant heat-absorbing electrode are placed in the electrolyte.

2. The flame-retardant heat-absorbing lithium battery as described in claim 1, characterized in that, A plurality of positive and negative electrode modules and at least two flame-retardant heat-absorbing electrode sheets are alternately stacked to form a battery cell, and the plurality of positive and negative electrode modules are connected in parallel. The battery cell is placed in the electrolyte in a flat state.

3. The flame-retardant heat-absorbing lithium battery as described in claim 1, characterized in that, Several positive and negative electrode modules are laid flat in sequence, and flame-retardant heat-absorbing plates are stacked on the top surface of several positive and negative electrode modules, and flame-retardant heat-absorbing plates are stacked on the bottom surface of several positive and negative electrode modules, and several positive and negative electrode modules are connected in parallel.

4. The flame-retardant heat-absorbing lithium battery as described in claim 2 or 3, characterized in that, The positive and negative electrode module includes a negative electrode plate, a separator, and a positive electrode plate stacked in sequence. The positive electrode plate is attached to one side of the fragile shell, and the negative electrode plate is attached to the other side of the fragile shell.

5. The flame-retardant heat-absorbing lithium battery as described in claim 1, characterized in that, At least two of the flame-retardant heat-absorbing electrodes are arranged on an ion-conducting membrane to form a flame-retardant heat-absorbing integrated sheet. The positive and negative electrode modules are stacked with the flame-retardant heat-absorbing integrated sheet to form a battery cell. The battery cell is placed in an electrolyte in a curled state.

6. The flame-retardant heat-absorbing lithium battery as described in claim 5, characterized in that, The positive and negative electrode module includes a second positive electrode plate, a second separator, a second negative electrode plate, and a third separator stacked in sequence, with the third separator attached to one side of the fragile shell.

7. The flame-retardant heat-absorbing lithium battery as described in claim 5, characterized in that, The flame-retardant heat-absorbing electrodes are arranged longitudinally, with several longitudinally arranged flame-retardant heat-absorbing electrodes on the ion-conductive membrane, and a spacer area is provided between adjacent flame-retardant heat-absorbing electrodes.

8. The flame-retardant heat-absorbing lithium battery as described in claim 5, characterized in that, The flame-retardant heat-absorbing electrodes are arranged laterally, with at least two transverse flame-retardant heat-absorbing electrodes arranged on the ion-conductive membrane, and a gap is provided between adjacent flame-retardant heat-absorbing electrodes.

9. The flame-retardant heat-absorbing lithium battery as described in claim 1, characterized in that, The flame-retardant heat-absorbing material is specifically a flame-retardant heat-absorbing solid material or a flame-retardant heat-absorbing solvent.

Images