A power battery cell structure with phase change heat transfer electrode and its preparation method

Abstract

The present invention relates to a power battery cell structure with a phase-change heat transfer electrode, comprising a battery shell, a diaphragm arranged in a serpentine spiral to form a plurality of interlayers, a positive electrode sheet and a negative electrode sheet sequentially spaced in the plurality of interlayers, at least one positive electrode sheet and / or a negative electrode sheet being an ultra-thin metal heat spreader, and the ultra-thin metal heat spreader being connected to the battery shell. An ultra-thin metal heat spreader is used to partially or completely replace a conventional electrode sheet in a battery cell, and the good heat transfer and temperature equalization performance of the ultra-thin metal heat spreader is utilized to rapidly disperse the heat generated during the charging and discharging process from the inside of the power battery through the ultra-thin metal heat spreader and transfer it to the power battery shell for discharge, thereby avoiding overheating caused by local high temperature of the power battery, effectively improving the core thermal conductivity of the power battery, and enabling efficient heat dissipation and temperature equalization of the battery during high-rate charging and discharging. The present invention also relates to a method for preparing a power battery cell structure with a phase-change heat transfer electrode.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance battery design and manufacturing, and in particular to a power battery cell structure with a phase-change heat transfer electrode and a preparation method thereof. Background Art

[0002] New energy lithium battery is a new and stable energy storage type.

[0003] The first step in manufacturing a lithium-ion battery is to assemble the battery cells into electrodes. A lithium-ion battery cell primarily consists of a positive electrode, a negative electrode, and a separator separating the two. Currently, the main technologies for manufacturing battery cells are lamination and winding. Compared to winding, lamination offers significant advantages: lower internal resistance, greater capacitance per unit volume, and higher capacity density. Furthermore, battery thickness and volume can be easily controlled, meeting a variety of different requirements.

[0004] The lithium-ion battery stack cell of the prior art usually includes a diaphragm and multiple electrode sheets arranged in a serpentine shape to form multiple interlayers in the battery shell. The electrode sheets include positive and negative electrodes. Starting from one end of the diaphragm, the diaphragm, the positive electrode sheets and the negative electrode sheets are stacked in a Z shape, that is, the positive electrode sheets and the negative electrode sheets are alternately arranged in the multiple interlayers of the diaphragm.

[0005] It has the following technical problems: the core thermal conductivity of the power battery is low, and a large amount of heat is generated inside the battery cell during rapid charging and discharging, which is difficult to discharge in time. It is easy for local high temperature of the battery to cause overheating, and it is impossible to achieve efficient heat dissipation and temperature equalization of the battery during high-rate charging and discharging.

[0006] Therefore, it is urgent to explore suitable heat dissipation methods for laminated batteries and develop safe and efficient square shell power lithium battery cell structures. Summary of the Invention

[0007] In response to the technical problems existing in the prior art, one of the objectives of the present invention is to provide a power battery cell structure with a phase change heat transfer electrode, which has a high core thermal conductivity and can quickly transfer battery heat from the inside of the battery to achieve efficient heat dissipation and temperature uniformity of the battery during high-rate charging and discharging.

[0008] In response to the technical problems existing in the prior art, the second purpose of the present invention is to provide a method for preparing a power battery cell structure with a phase change heat transfer electrode. This method can be used to prepare a battery cell with high core thermal conductivity, which can quickly transfer battery heat from the inside of the battery, thereby achieving efficient heat dissipation and temperature uniformity of the battery during high-rate charging and discharging.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A power battery cell structure with a phase change heat transfer electrode includes a battery shell, in which a diaphragm arranged in a serpentine shape to form multiple interlayers is provided, and positive and negative electrode sheets are sequentially spaced within the multiple interlayers. The structure is characterized in that at least one positive electrode sheet and / or negative electrode sheet is an ultra-thin metal heat spreader, and the ultra-thin metal heat spreader is connected to the battery shell.

[0011] Furthermore, the thickness of the ultra-thin metal heat sink is less than 2 mm.

[0012] Furthermore, the thermal conductivity of the ultra-thin metal vapor chamber is greater than 800 W / mK.

[0013] Furthermore, when used as a negative electrode, the ultra-thin metal heat sink substrate is made of copper; when used as a positive electrode, the ultra-thin metal heat sink substrate is made of aluminum.

[0014] Furthermore, the battery housing is made of aluminum-plastic film, aluminum or steel.

[0015] A method for preparing a power battery cell structure with a phase-change heat transfer electrode comprises the following steps: disposing a diaphragm in a battery housing, wherein the diaphragm is arranged in a serpentine shape to form multiple interlayers;

[0016] The positive electrode sheets and the negative electrode sheets are sequentially arranged in the multiple interlayers;

[0017] Among them, at least one positive electrode sheet and / or negative electrode sheet is an ultra-thin metal heat spreader, and the ultra-thin metal heat spreader is connected to the battery casing.

[0018] Furthermore, the number of ultra-thin metal heat spreaders is adjusted accordingly according to the heat generated by the battery.

[0019] Furthermore, the positive electrode sheet, the negative electrode sheet and the ultra-thin metal heat sink are of the same size.

[0020] In general, the present invention has the following advantages:

[0021] An ultra-thin metal vapor chamber is used to partially or completely replace the conventional positive and / or negative electrodes in the battery cell. The ultra-thin metal vapor chamber has good heat transfer and temperature uniformity properties. The heat generated during the charging and discharging process inside the power battery can be quickly dissipated through the ultra-thin metal vapor chamber and transferred to the power battery casing for discharge, avoiding overheating caused by local high temperature in the power battery, effectively improving the core thermal conductivity of the power battery, and realizing efficient heat dissipation and temperature uniformity of the battery during high-rate charging and discharging. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the planar structure of the power battery cell structure of the present invention.

[0023] In the picture:

[0024] 1-diaphragm; 2-ultra-thin metal heat sink; 3-negative electrode; 4-positive electrode. DETAILED DESCRIPTION

[0025] High heat flux density has become a trend in today's electronic devices. Traditional high-thermal-conductivity materials such as copper, aluminum, and graphite sheets are no longer able to meet these heat dissipation requirements. Phase change heat transfer is one of the most efficient heat transfer modes, and vapor chambers are one of the most suitable heat dissipation components for ultra-thin, high-heat-flux conditions. They rely on the vaporization and condensation of internal working fluids to dissipate heat, resulting in thermal conductivity far higher than traditional heat dissipation devices, even reaching dozens to tens of times that of copper. They are currently widely used in mobile phones, laptops, and other fields.

[0026] Since the ultra-thin heat spreader still has very outstanding heat dissipation performance despite its ultra-thin thickness, it can be used to replace the original electrode material in the square-shell power lithium battery cell structure to achieve efficient heat dissipation performance. Therefore, the present invention has broad development prospects in the fields of new energy vehicles, intelligent robots, portable devices, etc.

[0027] The present invention will be described in further detail below.

[0028] Example 1

[0029] like Figure 1 As shown, a power battery cell structure with a phase change heat transfer electrode includes a diaphragm 1, an ultra-thin metal heat sink 2, a conventional negative electrode plate 3 and a conventional positive electrode plate 4.

[0030] The ultra-thin metal heat spreader 2 replaces the metal foil as the conventional negative electrode plate 3 and is layered together with other conventional electrodes in the diaphragm 1 .

[0031] In the existing technology, power batteries inevitably generate a large amount of heat during the charging and discharging process. In particular, excessive heat often accumulates at the electrode plates and is difficult to discharge in time, which can easily cause local high temperatures and lead to overheating, affecting the normal performance of the battery and shortening its service life.

[0032] This embodiment uses an ultra-thin metal vapor chamber 2 to partially or completely replace the negative electrode plate 3 in the battery cell. By utilizing the excellent heat transfer and temperature uniformity of the ultra-thin metal vapor chamber 2, the heat generated during the charging and discharging process inside the power battery can be quickly dispersed through the ultra-thin metal vapor chamber 2 and transferred to the power battery shell for discharge, so that the heat inside the square shell power lithium battery cell no longer accumulates too much on the negative electrode plate 3, avoiding local high temperature of the power battery and causing overheating, effectively improving the core thermal conductivity of the power battery, and realizing efficient heat dissipation and temperature uniformity of the battery during high-rate charging and discharging.

[0033] Furthermore, the thickness of the ultra-thin metal vapor chamber 2 used is preferably 1 mm, and the thermal conductivity is preferably 1500 W / mK, to ensure its efficient heat dissipation performance.

[0034] The ultra-thin metal heat sink 2 used as the negative electrode is made of copper and has the same size as the conventional negative electrode plate 3 and the conventional positive electrode plate 4.

[0035] In order to ensure that the thickness of the laminated battery is moderate, it is preferred to place a copper metal ultra-thin heat spreader every two electrode sheets.

[0036] The battery shell of the square-shell power lithium battery is made of aluminum-plastic film and is evacuated twice.

[0037] A method for preparing a power battery cell structure with a phase-change heat transfer electrode comprises the following steps: arranging a diaphragm 1 in a battery housing, wherein the diaphragm 1 is arranged in a serpentine shape to form multiple interlayers;

[0038] The positive electrode sheets 4 and the negative electrode sheets 3 are sequentially arranged in the multiple interlayers;

[0039] Among them, at least one positive electrode sheet 4 and / or negative electrode sheet 3 is an ultra-thin metal heat spreader 2, and the ultra-thin metal heat spreader 2 is connected to the battery housing.

[0040] The specific steps include:

[0041] 1. Front-end process

[0042] Mixing - coating - baking - rolling - cutting:

[0043] The slurry is applied to the ultra-thin metal vapor chamber 2 and the conventional electrode, and then rolled after baking. The conventional electrode is then cut into the same size as the ultra-thin metal vapor chamber 2 used.

[0044] 2. Mid-stage process

[0045] Lamination - hot pressing - packaging - baking - liquid injection - sealing - standing - secondary liquid injection - sealing - volume separation - sorting:

[0046] The various electrodes processed in the previous process are divided into positive electrodes and negative electrodes using a laminating machine, and then placed on both sides of the diaphragm 1 in sequence, keeping their edges aligned, and then proceeding with subsequent processes.

[0047] 3. Back-end process:

[0048] Individual cells are assembled into battery packs.

[0049] Example 2

[0050] The main difference between this embodiment and embodiment 1 is:

[0051] The ultra-thin metal heat spreader 2 is made of aluminum and replaces the metal foil as the conventional positive electrode plate 4 and is layered together with other conventional electrodes in the diaphragm 1 .

[0052] This embodiment uses an ultra-thin metal vapor chamber 2 to partially or completely replace the positive electrode plate 4 in the battery cell. By utilizing the excellent heat transfer and temperature uniformity of the ultra-thin metal vapor chamber 2, the heat generated during the charging and discharging process inside the power battery can be quickly dispersed through the ultra-thin metal vapor chamber 2 and transferred to the power battery shell for discharge, so that the heat inside the square shell power lithium battery cell is no longer excessively accumulated on the positive electrode plate 4, avoiding local high temperature of the power battery and causing overheating, effectively improving the core thermal conductivity of the power battery, and realizing efficient heat dissipation and temperature uniformity of the battery during high-rate charging and discharging.

[0053] Furthermore, the thickness of the ultra-thin metal vapor chamber 2 used is preferably 0.8 mm, and the thermal conductivity is preferably 1200 W / mK to ensure its efficient heat dissipation performance.

[0054] In order to ensure that the thickness of the stacked battery is moderate, it is preferred to place an aluminum metal ultra-thin heat spreader every two electrode sheets.

[0055] Example 3

[0056] The main difference between this embodiment and embodiment 1 is:

[0057] When the battery generates a large amount of heat, the ultra-thin metal heat spreader 2 is used to replace part of the conventional positive electrode sheet 4 and part of the conventional negative electrode sheet 3.

[0058] In the case of severe battery heating, the ultra-thin metal vapor chamber 2 completely replaces all conventional positive electrode sheets 4 and all conventional negative electrode sheets 3 .

[0059] The present invention has the following advantages:

[0060] (1) It can charge and discharge more efficiently, and even perform multi-rate charge and discharge applications without causing overheating of square-shell power lithium batteries. It is safer and more efficient than traditional square-shell power lithium batteries.

[0061] (2) It can effectively transfer the heat inside the laminated square shell power lithium battery structure, equalize the internal heat, and avoid excessive temperature at a certain point that affects performance or even damages the equipment.

[0062] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A power battery cell structure with a phase-change heat transfer electrode, comprising a battery housing, a separator arranged in a serpentine pattern to form multiple interlayers, and positive and negative electrode sheets spaced sequentially within the multiple interlayers, characterized in that: At least one positive electrode sheet and / or negative electrode sheet is an ultra-thin metal vapor chamber, and the ultra-thin metal vapor chamber is connected to the battery housing; The thickness of the ultra-thin metal vapor chamber is less than 2 mm; the thermal conductivity of the ultra-thin metal vapor chamber is greater than 800 W / mK.

2. A power battery cell structure with a phase change heat transfer electrode according to claim 1, characterized in that: When used as a negative electrode, the base material of the ultra-thin metal heat sink is copper; when used as a positive electrode, the base material of the ultra-thin metal heat sink is aluminum.

3. A power battery cell structure with a phase change heat transfer electrode according to claim 1, characterized in that: The battery casing is made of aluminum-plastic film, aluminum or steel.

4. A method for preparing a power battery cell structure having a phase change heat transfer electrode according to any one of claims 1 to 3, characterized in that: The following steps are included: A diaphragm is arranged in a battery housing, wherein the diaphragm is arranged in a serpentine shape to form a plurality of interlayers; The positive electrode sheets and the negative electrode sheets are sequentially arranged in the multiple interlayers; Among them, at least one positive electrode sheet and / or negative electrode sheet is an ultra-thin metal heat spreader, and the ultra-thin metal heat spreader is connected to the battery casing.

5. The method for preparing a power battery cell structure having a phase change heat transfer electrode according to claim 4, characterized in that: Adjust the number of ultra-thin metal heat sinks accordingly based on the heat generated by the battery.

6. The method for preparing a power battery cell structure having a phase change heat transfer electrode according to claim 4, characterized in that: The positive electrode sheet, the negative electrode sheet and the ultra-thin metal heat sink are of the same size.

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