Temperature measurement method of battery pack

Abstract

To provide a temperature measurement method of a battery pack, which can directly measure internal temperature of the battery pack in such a state that a temperature sensor is easily fixed to the inside of the battery pack having the highest temperature in use.SOLUTION: In a temperature measurement method for measuring the temperature of a battery pack in which a plurality of battery cells are arranged in parallel, a temperature measurement member is manufactured by arranging a fixation material around a temperature sensor, and is fixed by deformingly pressing the fixation material into gaps between the plurality of battery cells, so that the temperature sensor measures the temperature of the inside of the battery pack.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for measuring the temperature of a battery pack. [Background technology]

[0002] Conventionally, there has been known a battery pack (also called an "assembled battery") in which a plurality of battery cells are arranged and connected in series or parallel to each other to increase capacity. The battery pack is used, for example, as a driving source for an electric vehicle (EV).

[0003] Generally, a battery pack is guaranteed to operate within a specified temperature range. In other words, if a battery pack is used at an unexpected temperature, there is a risk of the battery performance deteriorating. For example, the temperature of a battery pack increases due to internal heat generation during use, so appropriate temperature management of the battery pack is important to ensure battery performance (see, for example, Patent Documents 1-3). Patent Document 1 discloses a method of measuring the temperature of a battery pack by fixing a temperature sensor (e.g., a thermistor or a thermocouple) inside the battery pack (at the center of the electrode of the battery cell).

[0004] In the temperature measurement method described in Patent Document 1, a fluid is sealed in the hollow space between the closed end of a tubular case and a temperature sensor fixed inside the case. This causes the fluid to deform in response to the thermal expansion of the battery cell during use, suppressing an increase in contact pressure and preventing damage to the battery cell. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-146693 A [Patent Document 2] Patent No. 5234365 [Patent Document 3] JP 2023-1774 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the temperature measurement method described in Patent Document 1, the position of the temperature sensor changes with the thermal expansion of the battery cell, and the measurement target part changes. Therefore, the temperature measurement result includes the influence of the change in the measurement target part, and in order to accurately manage the temperature of the battery pack, it is necessary to take into account the influence of the change in the measurement target part.

[0007] On the other hand, when a temperature sensor is directly fixed to a battery pack using an adhesive, the temperature of the battery pack can be easily managed because the measurement target portion does not change. However, since it is difficult to fix a temperature sensor inside a battery pack, it is not possible to directly measure the temperature inside the battery pack, which is the hottest during use. If the temperature sensor is fixed inside the battery pack using an adhesive, the inside of the battery pack will be soiled with the adhesive, and it is difficult to check whether the temperature sensor is fixed in the desired position.

[0008] An object of the present invention is to provide a method for measuring the temperature of a battery pack, which can easily attach a temperature sensor to the inside of the battery pack, which becomes the hottest during use, and directly measure the internal temperature. [Means for solving the problem]

[0009] The temperature measuring method according to the present invention comprises: A temperature measurement method for measuring a temperature of a battery pack in which a plurality of battery cells are arranged in parallel, comprising the steps of: A fixing material is placed around the temperature sensor to prepare a temperature measuring member; The temperature measuring member is press-fitted into the gaps between the plurality of battery cells while deforming the fixing material; The temperature sensor measures the temperature inside the battery pack. Effect of the Invention

[0010] According to the temperature measurement method of the present invention, a temperature sensor can be easily fixed inside the battery pack, which is the hottest part during use, to directly measure the internal temperature, thereby enabling accurate temperature management of the battery pack. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing an example of a battery pack to which the temperature measuring method of the present embodiment can be applied. [Diagram 2] FIG. 2 is a process diagram showing the temperature measuring method according to this embodiment. [Diagram 3] FIG. 3 is a diagram showing the configuration of a temperature measuring member used in the temperature measuring method of the present embodiment. [Figure 4] 4A and 4B are diagrams showing an example of an installation state of a temperature measurement member with respect to a battery pack. [Diagram 5] FIG. 5 is a diagram showing an example of the temperature measurement result. [Figure 6] 6A and 6B are diagrams showing modified examples of the temperature measuring member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0013] Fig. 1 is a perspective view showing an example of a battery pack 10 to which the temperature measurement method of the present embodiment can be applied. Fig. 2 is a process diagram showing the temperature measurement method of the present embodiment. Fig. 3 is a diagram showing the configuration of a temperature measurement member 20 used in the temperature measurement method of the present embodiment. Figs. 4A and 4B are diagrams showing the installation state of the temperature measurement member 20 relative to the battery pack 10. Fig. 4A is a plan view of the battery pack 10 seen from above, and Fig. 4B is a cross-sectional view taken along the arrow AA in Fig. 4A.

[0014] As shown in FIG. 1, a battery pack 10 is composed of a plurality of battery cells 11 arranged side by side. The battery cells 11 are connected to each other in series or parallel by, for example, a bus bar. The battery cells 11 may be cylindrical or rectangular, or may be laminated. In the battery pack 10 shown in FIG. 1, eight cylindrical battery cells 11 are arranged in two rows of four cells each, and are integrated together by a protective material 12 such as a heat shrink tube or a laminate film. Gaps 13 between the battery cells 11 are exposed to the outside, for example, through openings 12a provided in the protective material 12.

[0015] In this embodiment, when measuring the temperature of the battery pack 10, first, the temperature measurement member 20 is prepared (step S101 in FIG. 2). Next, the temperature measurement member 20 is inserted inside the battery pack 10 (step S102), and the temperature measurement member 20 is fixed at a predetermined position (step S103). Then, the temperature inside the battery pack 10 is measured by the temperature sensor 21 of the fixed temperature measurement member 20 (step S104). The temperature measurement method of this embodiment is characterized by a method in which the temperature measurement member 20 is installed inside the battery pack 10.

[0016] 3, the temperature measuring member 20 has a temperature sensor 21, a fixing material 22, and an exterior tube 23. The temperature sensor 21 is fixed to the exterior tube 23 via the fixing material 22.

[0017] The temperature sensor 21 has a sensor portion 211 that detects a change in temperature of the contact portion, and a lead portion 212 that transmits a detection signal of the sensor portion 211 to a measuring device (not shown). For example, a thermocouple or a thermistor can be used as the temperature sensor 21.

[0018] The temperature measuring member 20 is produced by inserting the temperature sensor 21 into the outer tube 23 and fixing the temperature sensor 21 to the outer tube 23 via a fixing material 22. In Fig. 3, the temperature sensor 21 is inserted so that the sensor portion 211 is located near one end (hereinafter referred to as the "tip") of the outer tube 23, and the fixing material 22 is disposed around the sensor portion 211.

[0019] For example, with the temperature sensor 21 inserted in the exterior tube 23, the exterior tube 23 is filled with a liquid fixing material 22 having fluidity. The liquid fixing material 22 hardens under predetermined conditions (for example, heat and pressure). The temperature sensor 21 is fixed to a predetermined position in the exterior tube 23 via the fixing material 22 so as not to move.

[0020] The temperature sensor 21 may be inserted into the exterior tube 23 in a state where the liquid fixing material 22 is filled, and then the fixing material 22 may be hardened. The tip of the exterior tube 23 may be blocked to prevent the fixing material 22 from leaking.

[0021] The exterior tube 23 and the fixing material 22 are elastically deformable according to the shape of the gaps 13 between the battery cells 11 when the temperature measurement member 20 is inserted into the battery pack 10. In addition, the exterior tube 23 and the fixing material 22 have heat resistance and insulating properties that can withstand heat generated by the battery pack 10.

[0022] The outer diameter of the exterior tube 23, i.e., the outer diameter of the temperature measurement member 20, is set to be slightly larger than the diameter of an inscribed circle inscribed in the gap 13 of the battery cell 11. When installing the temperature measurement member 20 inside the battery pack 10, the temperature measurement member 20 is press-fitted into the battery pack 10.

[0023] The thickness etc. of the exterior tube 23 is designed to ensure a strength (rigidity) sufficient to allow the temperature measurement member 20 to be inserted into the battery pack 10 without being impeded. The exterior tube 23 is formed of a resin material such as a varnished tube.

[0024] The fixing material 22 preferably has high wettability with respect to the exterior tube 23 and high adhesiveness (interface stability) with the exterior tube 23. This allows the temperature sensor 21 to be firmly fixed to a predetermined position on the exterior tube 23.

[0025] Moreover, it is preferable that the fixing material 22 has high thermal conductivity. This improves the reactivity of the temperature sensor 21 compared to a case where heat is transferred through air. As a material for the fixing material 22, for example, an elastic material such as silicone rubber is preferable.

[0026] When installing the temperature measurement member 20 in the battery pack 10, an operator inserts the tip of the temperature measurement member 20 into the gap 13 between the battery cells 11. The temperature measurement member 20 advances into the battery pack 10 while pressure is applied to the portion where the fixing material 22 is arranged. Because the exterior tube 23 has a predetermined rigidity, the temperature measurement member 20 can be smoothly pressed into the gap 13 without bending.

[0027] The worker finishes the insertion operation when the sensor portion 211 of the temperature sensor 21 reaches a predetermined position (for example, the center part of the battery pack 10). The temperature measurement member 20 is held inside the battery pack 10 by the surface pressure that the portion where the fixing member 22 is arranged receives from the battery cell 11. In other words, the temperature measurement member 20 can be easily fixed inside the battery pack 10 without using an adhesive.

[0028] Because heat generated by the battery cells is difficult to dissipate, the inside of the battery pack 10 tends to become hotter than the side of the battery pack 10. In this embodiment, the temperature measuring member 20 is appropriately fixed inside the battery pack 10, which becomes the hottest during use, and the temperature inside the battery pack 10 can be directly measured.

[0029] Fig. 5 is a diagram showing an example of a temperature measurement result when the temperature measurement method of the present embodiment is applied. Fig. 5 shows a temperature measurement result T1 when the temperature measurement method of the present embodiment is applied, and temperature measurement results T2 and T3 when the temperature measurement method of the comparative example is applied. Temperature measurement result T2 is a measurement result when temperature sensor 21 is attached to the side surface of battery pack 10 with adhesive. Temperature measurement result T3 is a measurement result when temperature sensor 21 is attached to the side surface of battery pack 10 by a method other than adhesive (for example, adhesive tape).

[0030] As shown in Figure 5, by applying the temperature measurement method of this embodiment, the temperature of the battery pack 10 can be measured 5°C higher than in the conventional method in which a temperature sensor 21 was installed on the side of the battery pack 10, and it was confirmed that this method is useful for appropriate temperature management of the battery pack 10.

[0031] [Variations] 6A and 6B are diagrams showing modified examples of the temperature measuring member 20. In FIG.

[0032] In the temperature measurement member 20 described in the embodiment, the fixing material 22 is arranged around the sensor portion 211 of the temperature sensor 21, but as shown in FIG. 6A, the fixing material 22 may be arranged around the lead portion 212 of the temperature sensor 21.

[0033] In addition, in the embodiment, the temperature sensor 21 is fixed to the exterior tube 23 via the fixing material 22, but as shown in Fig. 6B, the exterior tube 23 may not be provided and the fixing material 22 may be in direct contact with the battery cell 11. Furthermore, a case for accommodating the fixing material 22 may be provided only in the portion where the fixing material 22 is arranged.

[0034] As described above, the temperature measurement methods according to the embodiments and modifications have the following features either alone or in appropriate combination.

[0035] That is, the temperature measurement method according to the embodiment is a method for measuring the temperature of a battery pack 10 in which multiple battery cells 11 are arranged side by side, in which a fixing material 22 is placed around a temperature sensor 21 to create a temperature measurement member 20 (step S101 in FIG. 2), the temperature measurement member 20 is pressed into the gaps 13 between the multiple battery cells 11 while deforming the fixing material 22 to fix the temperature measurement member 20 (steps S102, S103), and the temperature inside the battery pack 10 is measured by the temperature sensor 21 (step S104).

[0036] According to the temperature measurement method of this embodiment, the elasticity of the fixing material 22 is utilized to fix the temperature sensor 21 in the gap 13 of the battery cell 11, so that the temperature sensor 21 can be easily fixed inside the battery pack 10, which is the hottest part during use, and the battery cell 11 is not soiled by adhesive. Furthermore, because the temperature inside the battery pack 10 can be measured directly and the part measured by the temperature sensor 21 does not change, there is no need to perform temperature correction processing, and the temperature of the battery pack 10 can be managed with high accuracy.

[0037] In this embodiment, the temperature sensor 21 is inserted into the exterior tube 23, and the temperature sensor 21 is fixed to the exterior tube 23 via the fixing material 22. In this way, by using an exterior tube 23 that is more rigid than the temperature sensor 21, the temperature measurement member 20 can be easily press-fitted into the gaps 13 of the battery cells 11 and fixed therein.

[0038] In the embodiment, the temperature sensor 21 has a sensor unit 211 that detects temperature changes, and a fixing material 22 is arranged around the sensor unit 211. As a result, heat from the battery cell 11 is transferred via the fixing material 22, so that the temperature change of the battery pack 10 is reflected in a short time, improving the responsiveness of the temperature sensor 21.

[0039] In the embodiment, silicone rubber is used as the material for forming the fixing material 22. This makes it possible to easily achieve the characteristics required for the fixing material 22 (e.g., moldability, elasticity, heat resistance, thermal conductivity, and insulation).

[0040] The invention made by the inventor has been specifically described above based on an embodiment, but the present invention is not limited to the above embodiment and can be modified within the scope of the gist of the invention.

[0041] For example, a plurality of temperature measuring members may be installed in one battery pack.

[0042] The temperature measurement method of the present invention can also be applied to things other than battery packs, for example, when a temperature measurement member is installed inside a part or device that is difficult to visually check, or in a location with a small working space.

[0043] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0044] 10 Battery pack 11 Battery Cell 20 Temperature measuring components 21 Temperature Sensor 22 Fixing material 23 Exterior tube

Claims

1. A temperature measurement method for measuring a temperature of a battery pack in which a plurality of battery cells are arranged in parallel, comprising the steps of: A fixing material is placed around the temperature sensor to prepare a temperature measuring member; The temperature measuring member is press-fitted into the gaps between the plurality of battery cells while deforming the fixing material; Measure the temperature inside the battery pack with the temperature sensor; Temperature measurement method.

2. Inserting the temperature sensor into an exterior tube; The temperature sensor is fixed to the exterior tube via the fixing material. The temperature measuring method according to claim 1 .

3. The temperature sensor has a sensor portion for detecting a temperature change, The fixing material is disposed around the sensor portion. The temperature measuring method according to claim 1 or 2.

4. The material forming the fixing material is silicone rubber. The temperature measuring method according to claim 1 or 2.

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