A heat-sealing structure for pouch batteries

Abstract

This utility model discloses a heat-sealing structure for soft-pack batteries, relating to the field of battery technology. The utility model includes a battery cell with an inner layer on its outer side. An insulating layer is coated on the sidewall of the inner layer, located near the battery cell. An elastomer, specifically a polyolefin elastomer, is added inside the inner layer. This utility model uses an insulating layer to effectively separate the inner layer from the electrolyte, preventing the inner layer from swelling and aging due to prolonged contact with the electrolyte, ensuring the sealing effect of the inner layer, preventing electrolyte leakage, and using an elastomer to increase the tear resistance of the inner layer, preventing cracking of the inner layer seal due to battery cell expansion.

Description

Technical Field

[0001] This utility model belongs to the field of battery technology, and in particular relates to a heat-sealing structure for soft-pack batteries. Background Technology

[0002] The application of electromechanical equipment brings many conveniences to people's lives and work. The operation of electromechanical equipment relies on electrical energy. Electromechanical equipment cannot operate normally without the supply of electrical energy. Therefore, it is necessary to supply sufficient electrical energy to electromechanical equipment so that it can work normally. A battery is an object that can supply electrical energy to electromechanical equipment. Types of batteries include lithium batteries, lead-acid batteries, fuel cells, and pouch batteries. In order to prevent the leakage of electrolyte in pouch batteries, a heat-sealing structure needs to be set on the outside of the battery cell. The heat-sealing structure mainly consists of an outer layer (nylon layer), a middle layer (aluminum foil layer), and an inner layer (PP material layer).

[0003] A search revealed a self-cleaning aluminum-plastic film and a soft-pack lithium battery in patent publication number CN220420718U. The patent includes, from the inside out, a low-temperature heat-sealing layer, a purification layer, an aluminum foil layer, a protective layer, and an adhesive layer between adjacent layers for connection. The purification layer is composed of a non-metallic filler layer and a polyethylene layer, which automatically absorbs moisture and impurities from the aluminum-plastic film, thus ensuring its dryness and cleanliness. This self-cleaning aluminum-plastic film and soft-pack lithium battery offers a simple structure, automatic moisture and impurity absorption, and high safety.

[0004] However, the heat-sealing structure of pouch batteries still has the following drawbacks in practical use:

[0005] First, prolonged contact between the inner layer and the electrolyte will cause the inner layer to swell and age, reducing its lifespan and causing the sealing effect of the inner layer to fail, resulting in electrolyte leakage and affecting the normal use of the soft-pack battery.

[0006] 2. Secondly, during the charging and discharging process, the internal chemical reaction of the battery cell will produce gas, which will cause it to expand. During the expansion process, the battery cell will exert external force on the inner layer, and may even cause the inner layer seal to crack, resulting in electrolyte leakage.

[0007] To address these issues, we provide a heat-sealing structure for pouch batteries. Utility Model Content

[0008] The purpose of this invention is to provide a heat-sealing structure for soft-pack batteries. By setting an isolation layer, the inner layer is prevented from being in long-term contact with the electrolyte, thus preventing swelling and aging and increasing service life. Furthermore, by setting an elastomer, the tear resistance of the inner layer is increased, preventing cracking of the inner layer seal edge, thereby solving the technical problems mentioned in the background art.

[0009] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0010] This utility model relates to a heat-sealing structure for a soft-pack battery, comprising a battery cell, an inner layer on the outer side of the battery cell, an insulating layer coated on the sidewall of the inner layer, the insulating layer being located on the side close to the battery cell; and an elastomer, which is a polyolefin elastomer, is added inside the inner layer.

[0011] The present invention is further configured such that the battery cell is provided with a positive electrode tab and a negative electrode tab, and the positive electrode tab and the negative electrode tab are symmetrically distributed.

[0012] The present invention is further configured such that the inner layer is a PP material layer and the isolation layer is a nano-ceramic coating.

[0013] The present invention is further configured such that an intermediate layer is adhered to the adhesive layer coated on the sidewall of the inner layer, and the intermediate layer is located on the side away from the isolation layer.

[0014] The present invention is further configured such that the intermediate layer is an aluminum foil layer and the adhesive layer is a polyethylene layer.

[0015] The present invention is further configured such that an outer layer is adhered to an adhesive layer coated on the sidewall of the intermediate layer, the outer layer being located on the side away from the inner layer, and the outer layer being a nylon layer.

[0016] This utility model has the following beneficial effects:

[0017] This invention features an isolation layer. The isolation layer is uniformly sprayed onto the inner layer near the battery cell using a spraying tool. The isolation layer is a nano-ceramic coating, which enhances barrier properties and effectively prevents swelling and aging of the inner layer after long-term contact with the electrolyte, thus preventing sealing failure, increasing the service life of the inner layer, and improving the sealing effect.

[0018] This invention incorporates an elastomer. The inner layer (PP material) and the elastomer (polyolefin elastomer) are placed in a mixing device and stirred to ensure thorough mixing. Due to the good plasticity of the elastomer, the tear resistance of the inner layer is improved, preventing the inner layer from cracking when the battery cell expands during charging and discharging, thus enhancing the sealing effect. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0020] Figure 1 This is a cross-sectional schematic diagram of a heat-sealing structure for a pouch battery.

[0021] Figure 2 for Figure 1 Enlarged schematic diagram of the structure at point A in the middle;

[0022] Figure 3 This is a three-dimensional schematic diagram of a heat-sealing structure for pouch batteries.

[0023] The attached diagram lists the components represented by each number as follows:

[0024] 1-Battery cell, 101-Positive tab, 102-Negative tab, 2-Inner layer, 3-Middle layer, 4-Outer layer, 5-Separation layer, 6-Elastomer, 7-Adhesive layer. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model. Example 1

[0026] Please see Figure 1 and Figure 3 This utility model is a heat-sealing structure for a soft-pack battery, including a battery cell 1, a positive electrode tab 101 and a negative electrode tab 102. The positive electrode tab 101 and the negative electrode tab 102 realize the positive and negative connection inside the battery cell and cooperate with the external circuit to transmit current during charging and discharging.

[0027] Specifically, the battery cell 1 is provided with a positive tab 101 and a negative tab 102;

[0028] Furthermore, the positive electrode tab 101 and the negative electrode tab 102 are symmetrically distributed;

[0029] The operation process of this embodiment is as follows: the positive electrode 101 and the negative electrode 102 are connected to external devices, the chemical energy inside the battery cell is converted into electrical energy, and the electrical energy is transmitted to external devices through the positive electrode 101 and the negative electrode 102. Example 2

[0030] Please see Figure 1 and Figure 2Based on the first specific embodiment, an inner layer 2 and an isolation layer 5 are provided. The isolation layer 5 prevents the inner layer 2 from being in long-term contact with the electrolyte, prevents the inner layer from swelling and aging, increases the service life of the inner layer 2, and improves the sealing effect.

[0031] Specifically, an isolation layer 5 is coated on the surface of the inner layer 2, and the isolation layer 5 is located on the side close to the battery cell 1;

[0032] Furthermore, the inner layer 2 is a PP material layer, and the isolation layer 5 is a nano-ceramic coating;

[0033] The operation process of this embodiment is as follows: the inner layer 2 is laid flat, the separator 5 is evenly sprayed on the surface of the inner layer 2 using a spraying tool, the inner layer 2 is folded in half with the separator 5 on the inside, the battery cell 1 is placed inside the inner layer 2, and the positive electrode tab 101 and the negative electrode tab 102 are located on the outside of the inner layer 2, and the inner layer 2 is sealed with a hot air device. Example 3

[0034] Please see Figure 1 and Figure 2 Based on specific embodiment one and specific embodiment two, an inner layer 2 and an elastomer 6 are provided. The elastomer 6 has good plasticity, which increases the tear resistance of the inner layer 2 and prevents the inner layer 2 from cracking due to the expansion of the battery cell 1 during charging and discharging, thus ensuring good sealing.

[0035] Specifically, an elastomer 6 is added inside the inner layer 2, an intermediate layer 3 is provided on the outer wall of the adhesive layer 7 coated on the outer wall of the inner layer 2, and an outer layer 4 is provided on the outer wall of the adhesive layer 7 coated on the outer wall of the intermediate layer 3.

[0036] Furthermore, the middle layer 3 is an aluminum foil layer, the outer layer 4 is a nylon layer, the elastomer 6 is a polyolefin elastomer, and the adhesive layer 7 is a polyethylene layer.

[0037] The operation process of this embodiment is as follows: the inner layer 2 and the elastomer 6 are placed in a mixing device according to a certain ratio and mixed. The mixture is injection molded. The adhesive layer 7 is uniformly coated on the inner layer 2. The intermediate layer 3 is laid flat on the adhesive layer 7. The intermediate layer 3 and the inner layer 2 are bonded together through the adhesive layer 7 by a hot pressing process. The pressure is controlled at 0.5~1MPa and the temperature is set at 120~150℃. Then, the adhesive layer 7 is uniformly coated on the intermediate layer 3. The outer layer 4 is laid flat on the adhesive layer 7. The intermediate layer 3 and the outer layer 4 are bonded together through the adhesive layer 7 by a hot pressing process. The pressure is controlled at 0.5~1MPa and the temperature is set at 120~150℃.

[0038] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A heat-sealing structure for a pouch cell, comprising a battery cell (1), characterized in that: The battery cell (1) has an inner layer (2) on its outer side, and an isolation layer (5) is coated on the side wall of the inner layer (2). The isolation layer (5) is located on the side close to the battery cell (1). An elastomer (6) is added inside the inner layer (2). The elastomer (6) is a polyolefin elastomer. The battery cell (1) is provided with a positive electrode tab (101) and a negative electrode tab (102), and the positive electrode tab (101) and the negative electrode tab (102) are symmetrically distributed.

2. The heat-sealing structure for a soft-pack battery according to claim 1, characterized in that: The inner layer (2) is a PP material layer, and the isolation layer (5) is a nano-ceramic coating; An intermediate layer (3) is bonded to an adhesive layer (7) coated on the sidewall of the inner layer (2), the intermediate layer (3) being located on the side away from the isolation layer (5); The intermediate layer (3) is an aluminum foil layer, and the adhesive layer (7) is a polyethylene layer; An outer layer (4) is bonded to an adhesive layer (7) coated on the sidewall of the intermediate layer (3). The outer layer (4) is located on the side away from the inner layer (2) and is a nylon layer.

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